feat: 5-day theme-level onboarding track from the "New here?" card (#30)

A self-paced onboarding track that introduces a new employee to every KB
theme in breadth (not depth), so they grasp how Respellion works day to
day and week to week. Offered as a CTA inside the Dashboard "New here?"
explainer card; always available regardless of enrollment.

Design:
- Theme is the trackable unit; the 5 "days" are a read-time presentation
  grouping, so re-chunking never loses progress. Completion is stored per
  theme in onboarding_completions.
- Per-theme overview generated lazily on first open (fast-tier
  emit_onboarding_overview tool), cached in onboarding_overviews keyed by
  theme + a topics_fingerprint that triggers regeneration when the theme's
  topic set changes.
- Reachable via /onboarding-track using the existing skipEnrollmentGate
  prop, decoupled from the 26-week curriculum (distinct from /onboarding,
  the enrollment page).

Backend:
- pb_migrations/1781200000_created_onboarding.js: two collections with
  authenticated-only rules and unique indexes; TEXT team_member_id (no
  relation) per the post-#18/#27 convention. Mirrored in
  scripts/setup-pb-collections.mjs.
- src/lib/onboardingService.js: pure helpers (orderThemes,
  distributeThemesIntoDays, computeTopicsFingerprint,
  computeOnboardingProgress, buildOnboardingPlan) + generation + I/O.
- db.js onboarding helpers use pb.filter() bindings (theme is free text).
- LLM tool + Zod schema + registry + simulation stub.

Frontend:
- src/pages/OnboardingTrack.jsx (day list, per-theme overview, completion
  banner, progress ring/day bar).
- Dashboard "New here?" card CTA + X/5-days progress chip (hidden when the
  KB has no themes).

Docs: data-model, generation-spec (§D), frontend-spec updated.

Verified: 22 new unit tests (npm test 134/134), eslint clean on changed
files, npm run build OK, PocketBase v0.30.4 boot applies the migration
(collections + unique indexes + authed rules confirmed), and a backend
contract check (upsert idempotency, unique-index guard, special-char
theme filtering).

Closes #30

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

src/lib/__tests__/onboardingService.test.js

@@ -0,0 +1,152 @@
+import { describe, expect, it } from 'vitest';
+import {
+  ONBOARDING_DAY_COUNT,
+  orderThemes,
+  distributeThemesIntoDays,
+  computeTopicsFingerprint,
+  computeOnboardingProgress,
+  buildOnboardingPlan,
+} from '../onboardingService';
+
+const sizes = (days) => days.map((d) => d.themes.length);
+
+describe('onboardingService pure helpers', () => {
+  it('exposes a 5-day guideline', () => {
+    expect(ONBOARDING_DAY_COUNT).toBe(5);
+  });
+
+  describe('orderThemes', () => {
+    const kb = ['Governance', 'Culture', 'Privacy', 'Process'];
+
+    it('orders by first appearance in the schedule, then appends the rest alphabetically', () => {
+      const schedule = [{ theme: 'Privacy' }, { theme: 'Governance' }];
+      expect(orderThemes(kb, schedule)).toEqual(['Privacy', 'Governance', 'Culture', 'Process']);
+    });
+
+    it('de-duplicates repeated schedule labels', () => {
+      const schedule = [{ theme: 'Privacy' }, { theme: 'Privacy' }, { theme: 'Culture' }];
+      expect(orderThemes(kb, schedule)).toEqual(['Privacy', 'Culture', 'Governance', 'Process']);
+    });
+
+    it('ignores schedule labels that are not real KB themes (e.g. merged-week labels)', () => {
+      const schedule = [{ theme: 'Privacy & Governance (merged)' }, { theme: 'Culture' }];
+      expect(orderThemes(kb, schedule)).toEqual(['Culture', 'Governance', 'Privacy', 'Process']);
+    });
+
+    it('falls back to pure alphabetical when the schedule is null/empty', () => {
+      expect(orderThemes(kb, null)).toEqual(['Culture', 'Governance', 'Privacy', 'Process']);
+      expect(orderThemes(kb, [])).toEqual(['Culture', 'Governance', 'Privacy', 'Process']);
+    });
+  });
+
+  describe('distributeThemesIntoDays', () => {
+    const themes = (n) => Array.from({ length: n }, (_, i) => `T${i + 1}`);
+
+    it('splits 10 themes evenly across 5 days', () => {
+      expect(sizes(distributeThemesIntoDays(themes(10)))).toEqual([2, 2, 2, 2, 2]);
+    });
+
+    it('front-loads the remainder (12 -> 3,3,2,2,2)', () => {
+      expect(sizes(distributeThemesIntoDays(themes(12)))).toEqual([3, 3, 2, 2, 2]);
+    });
+
+    it('handles 7 -> 2,2,1,1,1', () => {
+      expect(sizes(distributeThemesIntoDays(themes(7)))).toEqual([2, 2, 1, 1, 1]);
+    });
+
+    it('uses fewer days than the cap when there are fewer themes', () => {
+      const days = distributeThemesIntoDays(themes(3));
+      expect(sizes(days)).toEqual([1, 1, 1]);
+      expect(days.map((d) => d.day)).toEqual([1, 2, 3]);
+    });
+
+    it('returns [] for no themes', () => {
+      expect(distributeThemesIntoDays([])).toEqual([]);
+    });
+
+    it('preserves order and loses nothing', () => {
+      const input = themes(12);
+      const flat = distributeThemesIntoDays(input).flatMap((d) => d.themes);
+      expect(flat).toEqual(input);
+    });
+  });
+
+  describe('computeTopicsFingerprint', () => {
+    it('is order-independent', () => {
+      const a = computeTopicsFingerprint([{ id: 'x' }, { id: 'y' }, { id: 'z' }]);
+      const b = computeTopicsFingerprint([{ id: 'z' }, { id: 'x' }, { id: 'y' }]);
+      expect(a).toBe(b);
+    });
+
+    it('changes when a topic is added or removed', () => {
+      const base = computeTopicsFingerprint([{ id: 'x' }, { id: 'y' }]);
+      expect(computeTopicsFingerprint([{ id: 'x' }])).not.toBe(base);
+      expect(computeTopicsFingerprint([{ id: 'x' }, { id: 'y' }, { id: 'z' }])).not.toBe(base);
+    });
+
+    it('handles empty input', () => {
+      expect(typeof computeTopicsFingerprint([])).toBe('string');
+    });
+  });
+
+  describe('computeOnboardingProgress', () => {
+    const days = [
+      { day: 1, themes: ['A', 'B'] },
+      { day: 2, themes: ['C'] },
+    ];
+
+    it('does not count a partially-done day as complete', () => {
+      const p = computeOnboardingProgress(days, new Set(['A']));
+      expect(p).toMatchObject({ themesTotal: 3, themesDone: 1, dayCount: 2, daysCompleted: 0, allDone: false });
+      expect(p.percentage).toBe(33);
+    });
+
+    it('counts a fully-done day', () => {
+      const p = computeOnboardingProgress(days, new Set(['A', 'B']));
+      expect(p).toMatchObject({ themesDone: 2, daysCompleted: 1, allDone: false });
+    });
+
+    it('reports allDone only when every theme is complete', () => {
+      const p = computeOnboardingProgress(days, new Set(['A', 'B', 'C']));
+      expect(p).toMatchObject({ themesDone: 3, daysCompleted: 2, percentage: 100, allDone: true });
+    });
+
+    it('accepts an array as well as a Set', () => {
+      expect(computeOnboardingProgress(days, ['A', 'B', 'C']).allDone).toBe(true);
+    });
+
+    it('returns zeros for an empty plan', () => {
+      expect(computeOnboardingProgress([], new Set())).toEqual({
+        themesTotal: 0, themesDone: 0, dayCount: 0, daysCompleted: 0, percentage: 0, allDone: false,
+      });
+    });
+  });
+
+  describe('buildOnboardingPlan', () => {
+    const topics = [
+      { id: 't1', label: 'T1', theme: 'Privacy', complexity_weight: 2 },
+      { id: 't2', label: 'T2', theme: 'Culture', complexity_weight: 1 },
+      { id: 'f1', label: 'F1', theme: 'Privacy', type: 'fact' }, // excluded by buildThemeTopicMap
+    ];
+
+    it('builds themes (schedule-ordered), days, and a theme→topics map', () => {
+      const activeVersion = { schedule: [{ theme: 'Privacy' }, { theme: 'Culture' }] };
+      const plan = buildOnboardingPlan(topics, activeVersion);
+      expect(plan.themes).toEqual(['Privacy', 'Culture']);
+      expect(sizes(plan.days)).toEqual([1, 1]);
+      expect(plan.themeTopicMap.get('Privacy').map((t) => t.id)).toEqual(['t1']); // fact excluded
+    });
+
+    it('tolerates a stringified schedule and a missing version', () => {
+      const stringified = { schedule: JSON.stringify([{ theme: 'Culture' }]) };
+      expect(buildOnboardingPlan(topics, stringified).themes).toEqual(['Culture', 'Privacy']);
+      expect(buildOnboardingPlan(topics, null).themes).toEqual(['Culture', 'Privacy']);
+    });
+
+    it('returns an empty plan for an empty KB', () => {
+      const plan = buildOnboardingPlan([], null);
+      expect(plan.themes).toEqual([]);
+      expect(plan.days).toEqual([]);
+    });
+  });
+});