Add README, CLAUDE.md, INSTRUCTIONS.md, and CI workflow

- README.md: feature list, stack, project structure, deferred items
- CLAUDE.md: architecture, conventions, route map, CSS variable system,
  EventSub subscription table, data model, custom event names
- INSTRUCTIONS.md: step-by-step initial deploy guide (Twitch app
  registration through OBS setup and custom CSS/JS), plus git workflow,
  first push, GitHub Actions, branching, and update procedure
- .github/workflows/ci.yml: syntax check and import check on every push

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -0,0 +1,50 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+
+      - name: Syntax check
+        run: |
+          python3 -c "
+          import ast, sys, pathlib
+          errors = []
+          for f in pathlib.Path('app').rglob('*.py'):
+              try:
+                  ast.parse(f.read_text())
+              except SyntaxError as e:
+                  errors.append(f'{f}: {e}')
+          if errors:
+              for e in errors: print('SYNTAX ERROR:', e)
+              sys.exit(1)
+          files = list(pathlib.Path('app').rglob('*.py'))
+          print(f'All {len(files)} Python files OK')
+          "
+
+      - name: Import check
+        run: python -c "from app.main import app; print('App import OK')"
+        env:
+          DATABASE_URL: sqlite:///./test.db
+          SECRET_KEY: ci-test-secret-not-real
+          TWITCH_CLIENT_ID: ci-placeholder
+          TWITCH_CLIENT_SECRET: ci-placeholder
+          TWITCH_REDIRECT_URI: http://localhost:8000/auth/callback
+          APP_BASE_URL: http://localhost:8000