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/shared/components/LoadingSpinner.tsx

@@ -12,7 +12,7 @@ export function LoadingSpinner({ size = 'md', className = '' }: LoadingSpinnerPr
 
   return (
     <div
-      className={`${sizeClasses[size]} border-[var(--border-primary)] border-t-[var(--text-accent)] rounded-full animate-spin ${className}`}
+      className={`${sizeClasses[size]} border-[var(--border-subtle)] border-t-[var(--accent-primary)] rounded-full animate-spin ${className}`}
       role="status"
       aria-label="Loading"
     >
@@ -28,7 +28,7 @@ interface LoadingOverlayProps {
 export function LoadingOverlay({ message = 'Loading...' }: LoadingOverlayProps) {
   return (
     <div className="fixed inset-0 bg-black/50 backdrop-blur-sm flex items-center justify-center z-50">
-      <div className="bg-[var(--bg-primary)] border border-[var(--border-primary)] rounded-lg p-6 flex flex-col items-center gap-4">
+      <div className="bg-[var(--bg-primary)] border border-[var(--border-subtle)] rounded-lg p-6 flex flex-col items-center gap-4">
         <LoadingSpinner size="lg" />
         <p className="text-sm text-[var(--text-secondary)]">{message}</p>
       </div>