feat: INCLUDE_SOURCES config + TikTok/Instagram opt-in in NUX

* feat: INCLUDE_SOURCES config + TikTok/Instagram opt-in in NUX

- INCLUDE_SOURCES=tiktok,instagram in .env forces sources on for all
  query types, bypassing the tier system
- NUX shows opt-in modal after ScrapeCreators key is saved: "Also
  search TikTok and Instagram?" with honest call-usage warning
- Tier system preserved as default — override only when INCLUDE_SOURCES set

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: neutral call-usage copy — works for free and paid tiers

---------

Co-authored-by: Matt Van Horn <mvanhorn@MacBook-Pro.local>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/last30days.py

@@ -1735,6 +1735,18 @@ def main():
     search_run_tiktok = has_tiktok and qt.is_source_enabled("tiktok", query_type)
     search_run_instagram = has_instagram and qt.is_source_enabled("instagram", query_type)
     search_run_xiaohongshu = has_xiaohongshu
+
+    # INCLUDE_SOURCES override: force specific sources on regardless of tier
+    _include_sources = {s.strip().lower() for s in config.get('INCLUDE_SOURCES', '').split(',') if s.strip()}
+    if _include_sources:
+        if 'tiktok' in _include_sources and has_tiktok:
+            if not search_run_tiktok:
+                sys.stderr.write("[Config] INCLUDE_SOURCES override: forcing tiktok\n")
+                search_run_tiktok = True
+        if 'instagram' in _include_sources and has_instagram:
+            if not search_run_instagram:
+                sys.stderr.write("[Config] INCLUDE_SOURCES override: forcing instagram\n")
+                search_run_instagram = True
     if args.search:
         search_sources = parse_search_flag(args.search)
         has_reddit = "reddit" in search_sources