Add run deletion with filesystem cleanup

- New POST /run/<id>/delete route removes run from DB and deletes run directory
- Only allows deletion of non-active runs (blocks running/queued)
- Delete Run button shown in run_details.html header for non-active runs

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

web/routes/run.py

@@ -1,5 +1,6 @@
 import os
 import json
+import shutil
 import markdown
 from datetime import datetime
 from flask import Blueprint, render_template, request, redirect, url_for, flash, session, send_from_directory
@@ -393,6 +394,30 @@ def revise_book(run_id, book_folder):
     return redirect(url_for('run.view_run', id=new_run.id))
 
 
+@run_bp.route('/run/<int:id>/delete', methods=['POST'])
+@login_required
+def delete_run(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
+
+    if run.status in ['running', 'queued']:
+        flash("Cannot delete an active run. Stop it first.")
+        return redirect(url_for('run.view_run', id=id))
+
+    project_id = run.project_id
+
+    run_dir = os.path.join(run.project.folder_path, "runs", f"run_{run.id}")
+    if os.path.exists(run_dir):
+        shutil.rmtree(run_dir)
+
+    db.session.delete(run)
+    db.session.commit()
+
+    flash(f"Run #{id} deleted successfully.")
+    return redirect(url_for('project.view_project', id=project_id))
+
+
 @run_bp.route('/run/<int:id>/download_bible')
 @login_required
 def download_bible(id):