feat(briefing): hard-cut tear-down

Backend:
- Delete briefing services (pipeline, scheduler, conversations, profile, tools)
- Delete routes/briefing.py + remove blueprint registration
- Move _get_temp_unit into services/weather.get_temp_unit (reads top-level temp_unit setting)
- Rename briefing_preferences.py → rss_filtering.py (functions are RSS-specific)
- Strip briefing scheduler hooks from app.py
- Strip briefing scheduler call from routes/settings.py
- Update test imports (test_rss_service, test_tz_helpers)

Frontend:
- Delete BriefingView, BriefingSetupWizard, BriefingToolStatusRow
- Strip /briefing route + nav links (AppHeader, KnowledgeView)
- Strip Settings → Briefing tab + state + functions + imports
- Strip briefing-intermediate handling from ChatMessage
- Hide /news route + nav links (NewsView depended on briefing endpoints; orphaned in tree)
- Drop unused useSettingsStore from AppHeader

The Android BriefingScreen lives in a separate repo and is not touched here.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/fabledassistant/app.py

@@ -11,7 +11,6 @@ from fabledassistant.config import Config
 from fabledassistant.routes.admin import admin_bp
 from fabledassistant.routes.api import api
 from fabledassistant.routes.auth import auth_bp
-from fabledassistant.routes.briefing import briefing_bp
 from fabledassistant.routes.chat import chat_bp
 from fabledassistant.routes.export import export_bp
 from fabledassistant.routes.notes import notes_bp
@@ -75,7 +74,6 @@ def create_app() -> Quart:
     app.register_blueprint(admin_bp)
     app.register_blueprint(api)
     app.register_blueprint(auth_bp)
-    app.register_blueprint(briefing_bp)
     app.register_blueprint(chat_bp)
     app.register_blueprint(export_bp)
     app.register_blueprint(images_bp)
@@ -333,9 +331,7 @@ def create_app() -> Quart:
 
         asyncio.create_task(_delayed_backfill())
 
-        # Start briefing scheduler
-        from fabledassistant.services.briefing_scheduler import start_briefing_scheduler
-        await start_briefing_scheduler(asyncio.get_running_loop())
+        # Journal scheduler is wired up in Stage C (services/journal_scheduler).
 
         # Start event scheduler (reminders + CalDAV pull sync)
         from fabledassistant.services.event_scheduler import start_event_scheduler
@@ -349,8 +345,6 @@ def create_app() -> Quart:
 
     @app.after_serving
     async def shutdown():
-        from fabledassistant.services.briefing_scheduler import stop_briefing_scheduler
-        stop_briefing_scheduler()
         from fabledassistant.services.event_scheduler import stop_event_scheduler
         stop_event_scheduler()