Improve global market dashboard UX and settings

- Add global market dashboard APIs/assets and improve data robustness (incl. crypto heatmap by market cap)

- Enhance global market UI (map+heatmap layout, loading behavior, formatting, theme tweaks)

- Fix Settings LLM Provider select to render label/value options correctly

- Rename Indicator Community to Official Community and move it to the bottom

- Add search fallback when Google quota is exhausted

backend_api_python/migrations/add_notification_settings.sql

@@ -1,16 +0,0 @@
--- Migration: Add notification_settings column to qd_users table
--- Run this if you see error: column "notification_settings" does not exist
-
--- Add notification_settings column (if not exists)
-DO $$ 
-BEGIN
-    IF NOT EXISTS (
-        SELECT 1 FROM information_schema.columns 
-        WHERE table_name = 'qd_users' AND column_name = 'notification_settings'
-    ) THEN
-        ALTER TABLE qd_users ADD COLUMN notification_settings TEXT DEFAULT '';
-        RAISE NOTICE 'Column notification_settings added to qd_users';
-    ELSE
-        RAISE NOTICE 'Column notification_settings already exists';
-    END IF;
-END $$;