feat: public platform, admin console, templates, landing docs

Projects become publicly browsable after admin approval; management and
secret-adjacent reads (logs, variables, exec, connection URLs) require
owner/member/admin auth, and platform controls sit behind RequireAdmin.

- Backend: OptionalAuth middleware, read/authed/admin route groups,
  projects.is_approved + service_templates.owner_id migration,
  visibility-aware sqlc queries, admin overview/users/approval endpoints,
  EnsureAdminAccount bootstrap (ADMIN_* env), 30 seeded templates with
  owner CRUD, managed-database connection URLs gated owner+admin, fix
  DB.Stats() infinite recursion.
- Frontend: expandable persisted sidebar + clickable user menu, public
  landing page with searchable docs browser (GitHub sync, bundled
  snapshot + localStorage fallback), DocsBrowser shared with /docs,
  template create/edit/JSON-upload for owned templates, database create
  dialog, admin console (stats, approvals, project edit/delete, user
  admin toggles), HA/Security/Usage polish with dead CSS tokens mapped
  to real theme vars, anonymous-safe gating on every mutation control.
- Tests: safe window.localStorage access fixes happy-dom crashes in
  PlatformShell and canvas storage.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/src/features/workspace/canvas/ProjectCanvas.tsx

@@ -28,7 +28,7 @@ import {
   type CanvasNodeLayout,
   type ProjectCanvasMetadata,
 } from '../model';
-import { canvasStorageKey, loadCanvasMetadata, saveCanvasMetadata } from '../storage';
+import { hasCanvasMetadata, loadCanvasMetadata, saveCanvasMetadata } from '../storage';
 import { GroupNode, ServiceNode, type GroupNodeData, type ServiceNodeData } from './nodes';
 import {
   Plus,
@@ -287,7 +287,7 @@ function CanvasInner({ projectId, services, variablesByService, onAddService, on
     deleteMutation.isPending;
 
   useEffect(() => {
-    const hasStoredViewport = localStorage.getItem(canvasStorageKey(projectId)) !== null;
+    const hasStoredViewport = hasCanvasMetadata(projectId);
     const metadata = loadCanvasMetadata(projectId, services);
     const nextNodes = toFlowNodes(metadata, services, onOpenService);