Add run tagging (DB column + migration + route + UI)

- Added tags VARCHAR(300) column to Run model
- Added startup ALTER TABLE migration in app.py
- New POST /run/<id>/set_tags route saves comma-separated tags
- Tag badges + collapsible edit form in run_details.html header area

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

web/app.py

@@ -116,6 +116,14 @@ with app.app_context():
             _log("System: Added 'last_heartbeat' column to Run table.")
     except: pass
 
+    # Migration: Add 'tags' column if missing
+    try:
+        with db.engine.connect() as conn:
+            conn.execute(text("ALTER TABLE run ADD COLUMN tags VARCHAR(300)"))
+            conn.commit()
+            _log("System: Added 'tags' column to Run table.")
+    except: pass
+
     # Reset all non-terminal runs on startup (running, queued, interrupted)
     # The Huey consumer restarts with the app, so any in-flight tasks are gone.
     try: