fix: briefing refresh — weather not populated + workspace conv bleed

Two bugs:

1. Manual 'Refresh' button didn't refresh weather/RSS before compiling.
   The daily scheduler calls refresh_all_feeds + refresh_location_cache
   before run_compilation; the manual trigger route called run_compilation
   directly, reading a stale cache. Manual trigger now mirrors the
   scheduler: refresh feeds and all configured weather locations first.

2. Navigating to WorkspaceView during a long briefing compilation caused
   the workspace chat to show the briefing content. triggerNow awaits
   ~30-60s; on completion it called loadAll() → chatStore.fetchConversation
   which overwrote the workspace's currentConversation in the shared store.
   Fixed with a _mounted flag — all post-async state writes in BriefingView
   are now guarded so they no-op if the component has been unmounted.

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

src/fabledassistant/routes/briefing.py

@@ -242,12 +242,30 @@ async def get_conversation_messages(conv_id: int):
 @briefing_bp.route("/trigger", methods=["POST"])
 @_REQUIRE
 async def manual_trigger():
-    """Dev/admin endpoint to manually trigger a briefing compilation."""
+    """Manually trigger a briefing compilation, including a fresh data refresh."""
     data = await request.get_json() or {}
     slot = data.get("slot", "compilation")
     if slot not in ("compilation", "morning", "midday", "afternoon"):
         return jsonify({"error": "invalid slot"}), 400
 
+    # Refresh external data first (mirrors what the scheduler does)
+    try:
+        from fabledassistant.services.rss import refresh_all_feeds
+        config_raw = await get_setting(g.user.id, "briefing_config", "{}")
+        config = json.loads(config_raw) if isinstance(config_raw, str) else {}
+        await refresh_all_feeds(g.user.id)
+        for key, loc in config.get("locations", {}).items():
+            if loc.get("lat") and loc.get("lon"):
+                await weather_svc.refresh_location_cache(
+                    user_id=g.user.id,
+                    location_key=key,
+                    location_label=loc.get("label", key),
+                    lat=loc["lat"],
+                    lon=loc["lon"],
+                )
+    except Exception:
+        logger.warning("Pre-trigger refresh failed for user %d", g.user.id, exc_info=True)
+
     from fabledassistant.services.briefing_pipeline import run_compilation
 
     model = await get_setting(g.user.id, "default_model", "")