docs(ws3): record session 1c completion (boundaries enforcement)

- ARCH-CONSOLIDATION-2026-04.md: add Sessie 1c entry under WS-3 voortgang
- CLAUDE.md: add Frontend import boundaries section
- BACKLOG.md: add four follow-up tickets
  - TECH-AXIOS-STORE-COUPLING
  - TECH-DELETE-DEAD-VIEWS
  - TECH-WS3-BOUNDARIES-SUBZONES
  - TECH-WS3-BOUNDARIES-ROUTER-ZONE

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

CLAUDE.md

@@ -268,6 +268,24 @@ you are using available components rather than building custom ones.
 - Never: TypeScript `any` type (use proper types, generics, or `unknown` with type guards)
 - Never: import axios directly in a component (use `src/lib/axios.ts` via a composable)
 
+## Frontend import boundaries (apps/app/)
+
+`apps/app/` enforces a layered import architecture via
+`eslint-plugin-boundaries`. Ten zones (`types` → `utils` → `lib` →
+`plugins` / `composables` / `stores` / `navigation` → `components` →
+`layouts` → `pages`); each zone may only import from the zones below
+it in the matrix. Vendored `@core/` and `@layouts/` are exempt.
+Cross-zone violations are lint errors, not warnings.
+
+Matrix details + rationale: `dev-docs/WS-3-SESSION-1C-AUDIT.md`.
+Config: `apps/app/.eslintrc.cjs`.
+
+When adding a new file: pick the zone first. If your file imports
+from a zone the matrix forbids, the structural answer is usually to
+hoist a type to `types/` or extract a helper to `utils/` /
+`composables/` — not to disable the rule. Per-line disables are
+allowed only with a `TODO TECH-*` reference to a backlog item.
+
 ## Order of work for each new module
 
 1. Create and run migration(s)