feat(dashboard): complete CV branching dashboard with auth and full editing workflow

- Visual branch heritage tree with colored dots and connecting lines, depth-aware expand/collapse
- Dashboard 3-tab layout: Content (inline block editing + patch staging), Patches (diff view), Submissions (AI suggestions)
- Inline block editing: click to edit any CV block, stage edits, save as named branch with pre-filled patches
- Submissions tab: create applications, request AI tailoring suggestions, accept/reject per suggestion
- Simple hardcoded login (username/password via env vars LOGIN_USER/LOGIN_PASS, defaults admin/admin)
- Authentik OIDC integration: authorize redirect + callback exchange, configurable via NEXT_PUBLIC_AUTHENTIK_*
- Middleware protecting /dashboard with session cookie verification (HMAC-SHA256)
- Auth API routes: /api/auth/login, /api/auth/logout, /api/auth/callback, /api/auth/token
- Backend: GET/PATCH submission routes for listing submissions and accepting/rejecting AI suggestions
- API client: OIDC bearer token forwarding from client-readable cookie

https://claude.ai/code/session_01CdisLhbC2kVt2hxfJ7TNPf

apps/webapp/src/app/api/auth/logout/route.ts

@@ -0,0 +1,8 @@
+import { NextResponse } from 'next/server';
+
+export async function POST() {
+    const res = NextResponse.json({ ok: true });
+    res.cookies.delete('session');
+    res.cookies.delete('oidc_token');
+    return res;
+}