fix(scaffolding): rename create-ssp to create-frontend, fix 2 bugs it surfaced

Renamed scripts/create-ssp.mjs -> create-frontend.mjs (+ its WP-45 doc, npm
script, and every prose/command reference) since "ssp" reads as an acronym
where "create-frontend" says what it does.

Also fixes two real bugs found while running it for real during WP-61:
scripts/ci-local.sh was missing from RENAME_CONTENT_FILES (any --name'd
clone that keeps a backend would break `npm run ci`, still hardcoding
BigRegister.slnx), and plopfile.mjs's `gen:context` insertion into
.dependency-cruiser.js anchored on the `showcase: null,` line, which
create-ssp/create-frontend has already stripped by the time gen:context
runs in the same invocation — silently leaving a freshly scaffolded
context with no CONTEXT_ALLOWED fence entry at all. Re-anchored on the
`const CONTEXT_ALLOWED = {` line instead, which never moves.

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

.claude/skills/new-ssp/SKILL.md

@@ -14,7 +14,7 @@ business content. Keep the machinery, replace the domain.
 Clone this repo, `npm ci`, then mechanise the mechanical parts (WP-45):
 
 ```bash
-node scripts/create-ssp.mjs --name Kvk --context inschrijving
+node scripts/create-frontend.mjs --name Kvk --context inschrijving
 ```
 
 `--name` (PascalCase) replaces `BigRegister.*` everywhere; `--context` (lowercase Dutch
@@ -65,7 +65,7 @@ Work through that checklist, keeping the GREEN gate below passing at every step.
   `@registratie/ui/dashboard.page` — too much else hardcodes `/dashboard` (login's post-auth
   redirect, `authGuard`'s fallback, header nav/logo, breadcrumb trail, several stories/specs).
   The script rewrites its `loadComponent` to point at the freshly scaffolded `--context` page
-  instead (a `TODO(create-ssp)` stopgap landing page, not a real overview).
+  instead (a `TODO(create-frontend)` stopgap landing page, not a real overview).
 - `scripts/gen-snippets.mjs` (showcase-only) + its `package.json` script entry + its CI/
   `ci-local.sh` "showcase snippets drift" steps: deleted alongside `showcase/` — they run
   unconditionally, so leaving them breaks `npm run ci` immediately once `showcase/` is gone.