PROBLEM: Theme was stored in local theme.json inside Docker container.
Every deploy rebuilt container → all branding settings LOST.

FIX: Dual storage — writes to both local file AND Supabase.
Player app reads from Supabase API (persistent).

Changes:
1. New API: /api/branding.php
   - GET: returns full theme from platform_theme + platform_assets tables
   - POST save_theme: upserts values into platform_theme
   - POST save_asset: upserts asset URLs into platform_assets
   - Public endpoint (cached 60s)

2. theme.js updated:
   - Fetches from /api/branding.php instead of local theme.json
   - Same apply logic (CSS vars, animations, button shapes)

3. admin/branding.php updated:
   - Reads from Supabase on page load (not just local file)
   - Saves to BOTH local file AND Supabase on every edit
   - Auto-save JS still works (posts to same page → writes to Supabase)

Flow:
- Admin edits color → auto-save → PHP writes to Supabase + local
- Player opens app → theme.js fetches /api/branding.php → Supabase query
- Deploy happens → local file reset → Supabase still has all values ✅
- Admin page reloads → reads from Supabase → shows saved values ✅Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>