fix: hide Test Game button when debug mode is off

- Wrap navbar Test Game button in {% if debug_mode %}
- Add debug_mode as global Jinja template variable via engine_callback
- Button now only shows when DEBUG=true environment variable is set

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: JacobCoffee

src/scribbl_py/app.py

@@ -287,6 +287,7 @@ async def profile_redirect() -> Redirect:
         template_config = TemplateConfig(
             directory=template_dir,
             engine=JinjaTemplateEngine,
+            engine_callback=lambda engine: engine.engine.globals.update({"debug_mode": debug}),
         )
 
     # Build middleware stack

src/scribbl_py/templates/base.html

@@ -53,7 +53,8 @@
             </ul>
         </div>
         <div class="navbar-end gap-2">
-            <!-- Quick Test Game Button (debug) -->
+            {% if debug_mode %}
+            <!-- Quick Test Game Button (debug only) -->
             <button
                 id="navbar-test-game-btn"
                 class="btn btn-sm btn-outline btn-secondary hidden lg:flex"
@@ -65,6 +66,7 @@
                 </svg>
                 Test Game
             </button>
+            {% endif %}
 
             <!-- Theme Toggle -->
             <button id="theme-toggle" class="btn btn-ghost btn-circle" aria-label="Toggle theme">