fix: add app-specific templates dir to Jinja loader

App templates must override shared templates so calendar pages
can skip the post-specific meta block.

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

app.py

@@ -1,8 +1,10 @@
 from __future__ import annotations
 
 import path_setup  # noqa: F401  # adds shared_lib to sys.path
+from pathlib import Path
 
 from quart import g
+from jinja2 import FileSystemLoader, ChoiceLoader
 
 from shared.factory import create_base_app
 
@@ -40,6 +42,13 @@ async def events_context() -> dict:
 def create_app() -> "Quart":
     app = create_base_app("events", context_fn=events_context)
 
+    # App-specific templates override shared templates
+    app_templates = str(Path(__file__).resolve().parent / "templates")
+    app.jinja_loader = ChoiceLoader([
+        FileSystemLoader(app_templates),
+        app.jinja_loader,
+    ])
+
     # Calendars blueprint at root — standalone mode (no post nesting)
     app.register_blueprint(
         register_calendars(),