feat: production-harden app and finalize merge-ready UX/theme baseline

- complete tokenized theme preset system and admin style guide visibility
- refine dashboard layout/scroll behavior and shared async/request UI states
- add user nav-visibility settings across API, migration, and frontend stores
- harden security headers/CSP handling and related test coverage
- enforce CI repository hygiene + frontend contract/theme/build quality gates
- update docs/env references and make migration smoke test head-aware

frontend/package.json

@@ -8,6 +8,7 @@
     "build": "vue-tsc --noEmit && vite build",
     "preview": "vite preview --host 0.0.0.0 --port 4173",
     "typecheck": "vue-tsc --noEmit",
+    "check:theme-tokens": "node ./scripts/check_theme_tokens.mjs",
     "test": "vitest",
     "test:run": "vitest run"
   },