feat(dx): gen:context generator (WP-44)

npm run gen:context scaffolds a bounded context: folders + starter page, the @<ctx>/*
tsconfig alias, a dependency-cruiser boundary entry, and a lazy authGuard route.

Refactors .dependency-cruiser.js's per-context contextRule calls into a single
CONTEXT_ALLOWED map that every rule derives from, so adding a context is really one
config entry (verified behavior-preserving: same dep:check counts, same graph output).

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

package.json

@@ -23,6 +23,7 @@
     "gen": "plop",
     "gen:value-object": "plop value-object",
     "gen:form-machine": "plop form-machine",
+    "gen:context": "plop context",
     "serve:i18n": "ng build --configuration development --localize && node scripts/serve-i18n.mjs",
     "ci": "bash scripts/ci-local.sh",
     "e2e": "playwright test",