feat: Add fast startup fetch and background caching

- Add  for quick startup using first N feeds
- Add background thread for full fetch and caching
- Update  to use fast fetch
- Update docs and skills

engine/app/main.py

@@ -8,7 +8,7 @@ import time
 from engine import config
 from engine.display import BorderMode, DisplayRegistry
 from engine.effects import get_registry
-from engine.fetch import fetch_all, fetch_poetry, load_cache
+from engine.fetch import fetch_all, fetch_all_fast, fetch_poetry, load_cache, save_cache
 from engine.pipeline import (
     Pipeline,
     PipelineConfig,
@@ -208,7 +208,18 @@ def run_pipeline_mode_direct():
         if cached:
             source_items = cached
         else:
-            source_items, _, _ = fetch_all()
+            source_items = fetch_all_fast()
+            if source_items:
+                import threading
+
+                def background_fetch():
+                    full_items, _, _ = fetch_all()
+                    save_cache(full_items)
+
+                background_thread = threading.Thread(
+                    target=background_fetch, daemon=True
+                )
+                background_thread.start()
     elif source_name == "fixture":
         source_items = load_cache()
         if not source_items: