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/backend/internal/api/metrics.go

@@ -60,26 +60,19 @@ func handleGetServiceMetrics(c *gin.Context) {
 		return
 	}
 
-	userID, exists := c.Get("user_id")
-	if !exists {
-		c.JSON(http.StatusUnauthorized, gin.H{"error": "User not authenticated"})
-		return
-	}
-
-	var ownerID string
+	var projectID uuid.UUID
 	var status string
 	err = db.QueryRow(
-		`SELECT p.owner_id, COALESCE(s.status, '')
-		 FROM services s JOIN projects p ON s.project_id = p.id
-		 WHERE s.id = $1`,
+		`SELECT s.project_id, COALESCE(s.status, '')
+		 FROM services s WHERE s.id = $1`,
 		serviceID,
-	).Scan(&ownerID, &status)
+	).Scan(&projectID, &status)
 	if err != nil {
 		c.JSON(http.StatusNotFound, gin.H{"error": "Service not found"})
 		return
 	}
-	if ownerID != userID.(string) {
-		c.JSON(http.StatusForbidden, gin.H{"error": "Access denied"})
+	if _, allowed := projectReadAccess(c, db, projectID); !allowed {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Service not found"})
 		return
 	}