feat: add Primary message to the 3 wizard machines (RD-07)

Each wizard component re-derives the step-boundary decision the reducer
already owns: advance on a middle step, submit on the last step. This
ticket moves that decision into the machine, so RD-08 can replace the
component's guard with one dispatch.

Add a `Primary` message to each Msg union, and export a `primary(s)`
function next to the existing `next`/`submit` pair. `primary` is a
three-line branch that delegates to `next`/`submit` and writes no new
validation. Each machine tests "last step" in its own vocabulary, per
the ticket's Decisions block: `herregistratie` checks `step === 3`,
`intake` checks `currentStep(s) === 'review'`, `registratie` checks
`currentStep(s) === 'controle'`. `Next` and `Submit` stay in every
union and every reducer — `Primary` is purely additive.

Add 3 spec cases per machine (9 total): Primary advances from a
non-final step, Primary submits from the final step, and Primary is a
no-op outside the editing state. Each case also asserts the
equivalence the ticket requires for RD-08's migration:
`reduce(s, Primary)` equals `reduce(s, Next)` at a non-final step, and
equals `reduce(s, Submit)` at the final step.

Regenerate `behaviour-spec.mdx` for the 9 new `it()` titles.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/ssp/src/app/herregistratie/domain/herregistratie.machine.spec.ts

@@ -8,6 +8,7 @@ import {
   back,
   gaNaarStap,
   submit,
+  primary,
   resolve,
   reduce,
   WizardState,
@@ -104,6 +105,25 @@ describe('wizard.machine', () => {
   });
 });
 
+describe('primary', () => {
+  it('Primary advances to the next step from a non-final step', () => {
+    const s = toStep2('4160', '200'); // Editing, step 2 — not the final step
+    expect(reduce(s, { tag: 'Primary' })).toEqual(reduce(s, { tag: 'Next' }));
+    expect(expectTag(primary(s), 'Editing').step).toBe(3);
+  });
+
+  it('Primary submits from the final step', () => {
+    const s = toStep3('4160', '200'); // Editing, step 3 — the final step
+    expect(reduce(s, { tag: 'Primary' })).toEqual(reduce(s, { tag: 'Submit' }));
+    expect(primary(s).tag).toBe('Submitting');
+  });
+
+  it('Primary is a no-op from a non-editing state', () => {
+    const submitting = submit(toStep3('4160', '200'));
+    expect(primary(submitting)).toBe(submitting);
+  });
+});
+
 describe('reduce (message-driven)', () => {
   it('drives the full happy path via messages', () => {
     let s: WizardState = initial;

apps/ssp/src/app/herregistratie/domain/herregistratie.machine.ts

@@ -121,6 +121,13 @@ export function submit(s: WizardState): WizardState {
   return result.ok ? { tag: 'Submitting', data: result.value } : { ...s, errors: result.error };
 }
 
+/** The primary button's action: advance, or submit from the last step. No-op
+    outside Editing — this is the one decision `onPrimary()` used to make. */
+export function primary(s: WizardState): WizardState {
+  if (s.tag !== 'Editing') return s;
+  return s.step === 3 ? submit(s) : next(s);
+}
+
 /** Route an upload sub-message through the pure upload reducer (Editing only). */
 export function upload(s: WizardState, msg: UploadMsg): WizardState {
   if (s.tag !== 'Editing') return s;
@@ -152,6 +159,7 @@ export type WizardMsg =
   | { tag: 'Back' }
   | { tag: 'GaNaarStap'; step: 1 | 2 | 3 }
   | { tag: 'Submit' }
+  | { tag: 'Primary' }
   | { tag: 'Retry' }
   | { tag: 'SubmitConfirmed' }
   | { tag: 'SubmitFailed'; error: string }
@@ -170,6 +178,8 @@ export function reduce(s: WizardState, m: WizardMsg): WizardState {
       return gaNaarStap(s, m.step);
     case 'Submit':
       return submit(s);
+    case 'Primary':
+      return primary(s);
     case 'Retry':
       return s.tag === 'Failed' ? { tag: 'Submitting', data: s.data } : s;
     case 'SubmitConfirmed':

apps/ssp/src/app/herregistratie/domain/intake.machine.spec.ts

@@ -10,6 +10,7 @@ import {
   back,
   gaNaarStap,
   submit,
+  primary,
   resolve,
   reduce,
   IntakeState,
@@ -207,6 +208,33 @@ describe('submit', () => {
   });
 });
 
+describe('primary', () => {
+  // Same fixture as the 'submit' describe block above: buitenland answered 'nee',
+  // uren high enough to skip the scholing question.
+  const highUren = givenIntake(
+    { tag: 'SetAnswer', key: 'buitenlandGewerkt', value: 'nee' },
+    { tag: 'SetAnswer', key: 'uren', value: '4160' },
+  );
+
+  it('Primary advances to the next step from a non-final step', () => {
+    expect(currentStep(expectTag(highUren, 'Answering'))).toBe('buitenland'); // not the final step
+    expect(reduce(highUren, { tag: 'Primary' })).toEqual(reduce(highUren, { tag: 'Next' }));
+    expect(expectTag(primary(highUren), 'Answering').cursor).toBe(1);
+  });
+
+  it('Primary submits from the final step', () => {
+    const atReview = reduce(reduce(highUren, { tag: 'Next' }), { tag: 'Next' });
+    expect(currentStep(expectTag(atReview, 'Answering'))).toBe('review'); // the final step
+    expect(reduce(atReview, { tag: 'Primary' })).toEqual(reduce(atReview, { tag: 'Submit' }));
+    expect(primary(atReview).tag).toBe('Submitting');
+  });
+
+  it('Primary is a no-op from a non-editing state', () => {
+    const submitting = submit(reduce(reduce(highUren, { tag: 'Next' }), { tag: 'Next' }));
+    expect(primary(submitting)).toBe(submitting);
+  });
+});
+
 describe('reduce (message-driven happy path)', () => {
   it('drives abroad branch end to end', () => {
     let s: IntakeState = initial;

apps/ssp/src/app/herregistratie/domain/intake.machine.ts

@@ -200,6 +200,13 @@ export function submit(s: IntakeState): IntakeState {
   return r.ok ? { tag: 'Submitting', data: r.value } : { ...s, errors: r.error };
 }
 
+/** The primary button's action: advance, or submit from the review step. No-op
+    outside Answering — this is the one decision `onPrimary()` used to make. */
+export function primary(s: IntakeState): IntakeState {
+  if (s.tag !== 'Answering') return s;
+  return currentStep(s) === 'review' ? submit(s) : next(s);
+}
+
 export function resolve(s: IntakeState, r: Result<string, void>): IntakeState {
   if (s.tag !== 'Submitting') return s;
   return r.ok
@@ -213,6 +220,7 @@ export type IntakeMsg =
   | { tag: 'Back' }
   | { tag: 'GaNaarStap'; cursor: number }
   | { tag: 'Submit' }
+  | { tag: 'Primary' }
   | { tag: 'Retry' }
   | { tag: 'SubmitConfirmed' }
   | { tag: 'SubmitFailed'; error: string }
@@ -231,6 +239,8 @@ export function reduce(s: IntakeState, m: IntakeMsg): IntakeState {
       return gaNaarStap(s, m.cursor);
     case 'Submit':
       return submit(s);
+    case 'Primary':
+      return primary(s);
     case 'Retry':
       return s.tag === 'Failed' ? { tag: 'Submitting', data: s.data } : s;
     case 'SubmitConfirmed':

apps/ssp/src/app/registratie/domain/registratie-wizard.machine.spec.ts

@@ -17,6 +17,7 @@ import {
   setField,
   prefillAdres,
   submit,
+  primary,
   resolve,
   reduce,
 } from './registratie-wizard.machine';
@@ -248,6 +249,26 @@ describe('submit', () => {
   });
 });
 
+describe('primary', () => {
+  it('Primary advances to the next step from a non-final step', () => {
+    const s = toBeroepStepWithDiploma(); // Invullen, beroep step — not the final step
+    expect(currentStep(expectTag(s, 'Invullen'))).toBe('beroep');
+    expect(reduce(s, { tag: 'Primary' })).toEqual(reduce(s, { tag: 'Next' }));
+    expect(currentStep(expectTag(primary(s), 'Invullen'))).toBe('controle');
+  });
+
+  it('Primary submits from the final step', () => {
+    const s = toControleStep(); // Invullen, controle step — the final step
+    expect(reduce(s, { tag: 'Primary' })).toEqual(reduce(s, { tag: 'Submit' }));
+    expect(primary(s).tag).toBe('Indienen');
+  });
+
+  it('Primary is a no-op from a non-editing state', () => {
+    const indienen = toIndienen();
+    expect(primary(indienen)).toBe(indienen);
+  });
+});
+
 describe('reduce (message-driven happy path)', () => {
   it('adres and correspondentie set, Next advances from adres to beroep', () => {
     // Given the initial wizard.

apps/ssp/src/app/registratie/domain/registratie-wizard.machine.ts

@@ -287,6 +287,13 @@ export function submit(s: RegistratieState): RegistratieState {
   return r.ok ? { tag: 'Indienen', data: r.value } : { ...s, errors: r.error };
 }
 
+/** The primary button's action: advance, or submit from the controle step.
+    No-op outside Invullen — this is the one decision `onPrimary()` used to make. */
+export function primary(s: RegistratieState): RegistratieState {
+  if (s.tag !== 'Invullen') return s;
+  return currentStep(s) === 'controle' ? submit(s) : next(s);
+}
+
 /** Route an upload sub-message through the pure upload reducer (Invullen only). */
 export function upload(s: RegistratieState, msg: UploadMsg): RegistratieState {
   if (s.tag !== 'Invullen') return s;
@@ -312,6 +319,7 @@ export type RegistratieMsg =
   | { tag: 'Back' }
   | { tag: 'GaNaarStap'; cursor: number }
   | { tag: 'Submit' }
+  | { tag: 'Primary' }
   | { tag: 'Retry' }
   | { tag: 'SubmitConfirmed'; referentie: string }
   | { tag: 'SubmitFailed'; error: string }
@@ -342,6 +350,8 @@ export function reduce(s: RegistratieState, m: RegistratieMsg): RegistratieState
       return gaNaarStap(s, m.cursor);
     case 'Submit':
       return submit(s);
+    case 'Primary':
+      return primary(s);
     case 'Retry':
       return s.tag === 'Mislukt' ? { tag: 'Indienen', data: s.data } : s;
     case 'SubmitConfirmed':

docs/project/readable-codebase/RD-07-primary-message.md

@@ -0,0 +1,157 @@
+# RD-07 — Move the step-boundary decision into the 3 wizard machines
+
+Status: done
+Source: PLAN.md 1a
+
+## Why
+
+Each wizard component decides in the UI whether the primary button means "next step" or
+"submit", duplicating a rule the reducer already owns:
+
+| Component                            | Line    | Body                                                                             |
+| ------------------------------------ | ------- | -------------------------------------------------------------------------------- |
+| `herregistratie-wizard.component.ts` | 256-259 | `if (s.tag !== 'Editing') return;` then `s.step < 3 ? Next : Submit`             |
+| `intake-wizard.component.ts`         | 368-371 | `if (s.tag !== 'Answering') return;` then `step() === 'review' ? Submit : Next`  |
+| `registratie-wizard.component.ts`    | 613-616 | `if (s.tag !== 'Invullen') return;` then `step() === 'controle' ? Submit : Next` |
+
+Each already-exported `next`/`submit` pair holds the real transition, so the component is
+re-deriving a decision the machine can make. After this ticket, `onPrimary()` in RD-08 becomes
+a single `dispatch({ tag: 'Primary' })`, and the wizard shell's `primary`/`back`/`retry`
+outputs map 1:1 onto messages — which is what `.claude/skills/form-machine/SKILL.md:74-78`
+already claims they do.
+
+This ticket is **domain-only**: machines and their specs. No component changes.
+
+## Read first
+
+- `apps/ssp/src/app/herregistratie/domain/herregistratie.machine.ts` — `next` at 87,
+  `submit` at 118, `reduce`'s `Next`/`Submit` cases at 165/171
+- `apps/ssp/src/app/herregistratie/domain/intake.machine.ts` — `currentStep` at 86, `next` at
+  173, `submit` at 197, cases at 226/232
+- `apps/ssp/src/app/registratie/domain/registratie-wizard.machine.ts` — `currentStep` at 96,
+  `next` at 265, `submit` at 284, cases at 337/343
+- The three matching `*.machine.spec.ts` files
+- CLAUDE.md decision 3 (state, and the naming rule for machines)
+
+## Decisions (pre-made, don't relitigate)
+
+1. **Add `{ tag: 'Primary' }` to each of the three `Msg` unions**, plus an exported
+   `primary(s)` function, plus a `case 'Primary'` in each `reduce` that delegates to it. Same
+   shape as the existing `Next`/`Submit` cases.
+
+2. **Express "last step" in each machine's own vocabulary. Do NOT invent a shared
+   `isLastStep` helper.** The three state shapes genuinely differ:
+   - `herregistratie`: `Editing` carries `step: 1 | 2 | 3` and there is **no `STEPS` array** →
+     the test is `s.step === 3`.
+   - `intake`: `Answering` carries `cursor: number` against
+     `STEPS = ['buitenland','werk','review']` → the test is `currentStep(s) === 'review'`.
+   - `registratie`: `Invullen` carries `cursor: number` against
+     `STEPS = ['adres','beroep','controle']` → the test is `currentStep(s) === 'controle'`.
+
+   Two of the three could share a `cursor === STEPS.length - 1` form, but the third cannot.
+   A helper covering two of three, plus a special case, is more to read than three plain
+   expressions.
+
+3. **`primary` delegates to the existing exported `next` and `submit`.** Write no new
+   validation and duplicate no transition logic. The whole function is a branch:
+
+   ```ts
+   export function primary(s: WizardState): WizardState {
+     if (s.tag !== 'Editing') return s;
+     return s.step === 3 ? submit(s) : next(s);
+   }
+   ```
+
+   (…and the equivalent, in its own vocabulary, for the other two.)
+
+4. **The guard moves into the machine.** `primary` returns `s` unchanged when the state is not
+   the editing state, so RD-08 can delete the component preamble. Note the editing tag differs
+   per machine: `Editing`, `Answering`, and `Invullen`. **`Invullen`/`Indienen`/`Ingediend`/
+   `Mislukt` are correct Dutch domain tags per CLAUDE.md — do not "fix" them to English.**
+
+5. **KEEP `Next` and `Submit` in all three `Msg` unions.** Verified: they are dispatched
+   across **9 spec files**, including `intake.acceptance.spec.ts`, which uses them as a
+   readable behaviour narrative, and the three `*-has-progress.spec.ts` files. Removing them
+   would rewrite dozens of spec lines for no gain. `Primary` is purely **additive**.
+
+6. **Do not touch any component.** RD-08 migrates the three wizards. If you edit a
+   `*.component.ts` in this ticket, it is out of scope.
+
+7. **Keep `SCHOLING_THRESHOLD_DEFAULT` greppable.** `npm run check:seam` greps for it as a
+   top-level `export const` in `intake.machine.ts:43`. Do not move or inline it.
+
+## Files
+
+- `apps/ssp/src/app/herregistratie/domain/herregistratie.machine.ts` + `.spec.ts`
+- `apps/ssp/src/app/herregistratie/domain/intake.machine.ts` + `.spec.ts`
+- `apps/ssp/src/app/registratie/domain/registratie-wizard.machine.ts` + `.spec.ts`
+
+## Steps
+
+1. In each machine: add `{ tag: 'Primary' }` to the `Msg` union, export `primary(s)` next to
+   `next`/`submit`, and add the `case 'Primary'` to `reduce`.
+2. In each machine spec: add the three cases from Acceptance below.
+3. Run `npm run gen:behaviour-spec` — new `it()` titles otherwise fail the drift check.
+4. Update this ticket's `Status:` to `done` and the README's RD-07 row to `done`.
+5. Commit all of it together.
+
+## Acceptance criteria
+
+Three cases per machine spec (9 total), pure `reduce` calls, no TestBed:
+
+```
+- Primary advances to the next step from a non-final step
+- Primary submits from the final step
+- Primary is a no-op from a non-editing state
+```
+
+The third case is what lets RD-08 delete the component guard, so do not skip it.
+
+```bash
+npm test          # exits 0
+npm run ci        # exits 0
+```
+
+Prove `Primary` produces exactly what the components produce today, so the migration in RD-08
+is behaviour-preserving. For each machine, these must be equal:
+
+```
+reduce(s, { tag: 'Primary' })  ===  reduce(s, { tag: 'Next' })      // at a non-final step
+reduce(s, { tag: 'Primary' })  ===  reduce(s, { tag: 'Submit' })    // at the final step
+```
+
+Prove nothing was removed:
+
+```bash
+grep -c "tag: 'Next'\|tag: 'Submit'" apps/ssp/src/app/herregistratie/domain/intake.machine.ts
+# Next and Submit must still be in the union and still handled in reduce
+```
+
+## Verification
+
+`npm run ci`. This ticket touches no story, no `.mdx` and no component, so `--full` is not
+required.
+
+## Out of scope
+
+- The three components. RD-08.
+- `besluit.machine.ts` and `change-request.machine.ts` — single-step forms with no step
+  boundary, so `Primary` would mean nothing there. RD-06 handles those two.
+- Removing `Next`/`Submit` (decision 5).
+- Renaming the Dutch tags in `registratie-wizard.machine.ts` (decision 4).
+
+## Risks
+
+- **`behaviour-spec.mdx` drift.** 9 new `it()` titles across 3 spec files.
+  `scripts/ci-local.sh` regenerates `libs/shared/docs/behaviour-spec.mdx` from a path-sorted
+  walk of spec titles and fails on any drift. Run `npm run gen:behaviour-spec` in the same
+  commit.
+- **`check:seam`** greps `SCHOLING_THRESHOLD_DEFAULT` (decision 7) and
+  `besluit.machine.ts`'s `BESLUIT_TAGS`. Neither should move, but if `check:seam` fails, that
+  is why.
+- **`snippets.generated.ts` drift.** `intake.machine.ts:59` carries a
+  `// #region showcase:steps` marker around `STEPS`. If your edit moves or splits that region,
+  run `npm run gen:snippets` in the same commit.
+- **Do not make `primary` clever.** It is a three-line branch delegating to two existing
+  functions. If it grows validation, error mapping, or a cursor calculation, the transition
+  logic has been duplicated instead of reused.

docs/project/readable-codebase/README.md

@@ -101,7 +101,7 @@ two. Note that RD-15 exists because 22 abandoned agent worktrees are still on di
 | RD-04 | Story titles to `Domein/<Context>/<Name>`; add the missing stories           | 03         | yes       | todo   |
 | RD-05 | `createStore` gains the effect map + specs                                   | 02         |           | done   |
 | RD-06 | **Bug fix:** 2 single-step forms to the effect map + retry affordance        | 05         | yes       | done   |
-| RD-07 | Add `Primary` to the 3 wizard machines + specs                               | 05         |           | todo   |
+| RD-07 | Add `Primary` to the 3 wizard machines + specs                               | 05         |           | done   |
 | RD-08 | Migrate the 3 wizards to the effect map + `Primary`                          | 07         | yes       | todo   |
 | RD-09 | **Docs + generator:** `form-machine.hbs`, ARCHITECTURE, fp-tea, skill        | 08         |           | todo   |
 | RD-10 | `WizardStatus` to a payload-carrying `WizardPhase`                           | 08         | yes       | todo   |

libs/shared/docs/behaviour-spec.mdx

@@ -20,7 +20,7 @@ tested where._
 
 Every bullet below is a real test name from the suite — an `it()` title (frontend) or a test
 method name (backend), read as a sentence. Nothing here is hand-written prose: this page
-**is** the suite, reshaped for a business reader. 510 frontend behaviours across
+**is** the suite, reshaped for a business reader. 519 frontend behaviours across
 9 contexts; 261 backend behaviours across 42 test
 classes.
 
@@ -383,6 +383,15 @@ classes.
 - gaNaarStap jumps back to an earlier step, clearing errors
 - gaNaarStap ignores a same/forward jump and jumps outside Answering
 
+#### primary
+
+- Primary advances to the next step from a non-final step
+- Primary submits from the final step
+- Primary is a no-op from a non-editing state
+- Primary advances to the next step from a non-final step
+- Primary submits from the final step
+- Primary is a no-op from a non-editing state
+
 #### reduce (message-driven happy path)
 
 - drives abroad branch end to end
@@ -605,6 +614,12 @@ classes.
 - a diploma with questions blocks Next until they are answered
 - validateAll keeps only the answers to the questions that applied
 
+#### primary
+
+- Primary advances to the next step from a non-final step
+- Primary submits from the final step
+- Primary is a no-op from a non-editing state
+
 #### reduce (message-driven happy path)
 
 - adres and correspondentie set, Next advances from adres to beroep