Release 0.13.0: cookie/privacy consent banner + policy pages (instrumentation prep)

Roadmap item #11. Ships the non-modal bottom-of-page cookie consent
banner, the default /privacy and /cookies policy pages, the
`cookie_consent` table + two §17 endpoints for server-side persistence,
the localStorage fallback for anonymous viewers, the /settings
"Privacy & cookies" tab for revisiting the choice, and the
`frontend/src/lib/consent.js` helper that roadmap item #13's analytics
SDK (v0.15.0) will gate against. No analytics SDK ships in this release
— the consent infrastructure goes in first so the gate is already in
place. Adds SPEC §14.5 / §14.6, lists two new endpoints in §17, names
the new table in §5, and surfaces four §19.2 candidates (content-repo
file vs env-var policy, GPC / DNT headers, i18n, item-#13 dependency).
Two new optional env vars (`VITE_PRIVACY_POLICY_URL`,
`VITE_COOKIES_POLICY_URL`) — defaults render the framework's stub
pages.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "rfc-app-frontend",
   "private": true,
-  "version": "0.7.0",
+  "version": "0.13.0",
   "type": "module",
   "scripts": {
     "dev": "vite",