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/routes/run.py

@@ -394,6 +394,22 @@ def revise_book(run_id, book_folder):
     return redirect(url_for('run.view_run', id=new_run.id))
 
 
+@run_bp.route('/run/<int:id>/set_tags', methods=['POST'])
+@login_required
+def set_tags(id):
+    run = db.session.get(Run, id)
+    if not run: return "Run not found", 404
+    if run.project.user_id != current_user.id: return "Unauthorized", 403
+
+    raw = request.form.get('tags', '')
+    tags = [t.strip() for t in raw.split(',') if t.strip()]
+    run.tags = ','.join(dict.fromkeys(tags))
+    db.session.commit()
+
+    flash("Tags updated.")
+    return redirect(url_for('run.view_run', id=id))
+
+
 @run_bp.route('/run/<int:id>/delete', methods=['POST'])
 @login_required
 def delete_run(id):