fix: YouTube timeout bump to 90s + Reddit 429 fail-fast

YouTube: Add youtube_future timeout key (60/90/120s for quick/default/deep)
separate from the shared future timeout. YouTube needs more time because
it does search + parallel transcript fetching. Previously, 20 videos +
5 transcripts exceeded the 60s budget and all results were discarded.

Reddit 429: Propagate rate-limit errors instead of swallowing them.
Enrichment now uses 10s timeout / 1 retry (was 30s / 3 retries).
On first 429, cancel remaining enrichment and skip Phase 2 Reddit.
Total time wasted on 429 drops from ~75s to ~12s.

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

scripts/lib/openai_reddit.py

@@ -235,7 +235,7 @@ def search_subreddits(
                 "Accept": "application/json",
             }
 
-            data = http.get(full_url, headers=headers, timeout=15)
+            data = http.get(full_url, headers=headers, timeout=15, retries=1)
 
             # Reddit search returns {"data": {"children": [...]}}
             children = data.get("data", {}).get("children", [])
@@ -267,6 +267,9 @@ def search_subreddits(
 
         except http.HTTPError as e:
             _log_info(f"Subreddit search failed for r/{sub}: {e}")
+            if e.status_code == 429:
+                _log_info("Reddit rate-limited (429) — skipping remaining subreddits")
+                break
         except Exception as e:
             _log_info(f"Subreddit search error for r/{sub}: {e}")