fix: improve title, summary, and content formatting

- youtube.py: fetch real title via YouTube oEmbed API instead of falling back to video ID
- youtube.py: paragraphize transcript text by grouping sentences (4 per para)
- enricher.py: increase max_tokens 1024→2048 to prevent summary truncation
- web.py: restore paragraph breaks after HTML stripping

core/enricher.py

@@ -64,7 +64,7 @@ def enrich(content_type: str, title: str, url: str, text: str) -> dict:
         client = _get_client()
         req = GenericChatRequest(
             messages=[UserMessage(content=[TextContent(text=prompt)])],
-            max_tokens=1024,
+            max_tokens=2048,
             temperature=0,
         )
         det = ChatDetails(