Fix 500 on customer revision when revision_history table is missing

Deployed databases can persist without the revision_history table,
causing /play/<token>/revise to crash with sqlite3.OperationalError.

- log_revision() now creates the table on the fly if it is missing.
- app.py runs init_db() at import time (safe CREATE TABLE IF NOT EXISTS)
  so new deployments auto-create missing tables on startup.

Bump patch version 0.4.0 -> 0.4.1.

README.md

@@ -1,6 +1,6 @@
 # Theme Song Booth
 
-**Version:** `v0.4.0`
+**Version:** `v0.4.1`
 
 A Flask web app for a convention booth where visitors request a custom AI-generated theme song, the operator manages the queue, and the final MP3(s) are delivered by email after payment.
 

VERSION

@@ -1 +1 @@
-0.4.0
+0.4.1

app.py

@@ -1493,3 +1493,16 @@ def init_db_command():
 if __name__ == '__main__':
     # Development-only entry point. Production uses gunicorn (see Dockerfile).
     app.run(debug=True, host='0.0.0.0')
+
+
+# Ensure the database file and expected tables exist when the app is imported by
+# gunicorn in production. init_db() uses CREATE TABLE IF NOT EXISTS, so this is
+# safe to run on every startup without wiping data.
+with app.app_context():
+    try:
+        init_db()
+    except Exception:
+        # If the database path is not yet reachable (e.g. volume not mounted),
+        # defer to the first request or the explicit init-db command.
+        import logging
+        logging.getLogger('app').warning('Startup init_db() failed; database may need manual initialization.', exc_info=True)

models.py

@@ -184,8 +184,9 @@ def delete_request(request_id):
 
 
 def log_revision(request_id, revision_count, note, old_a=None, old_b=None, new_a=None, new_b=None):
-    """Record a revision event in the revision_history table."""
+    """Record a revision event in the revision_history table, creating the table if it is missing."""
     db = get_db()
+    try:
         db.execute(
             """INSERT INTO revision_history
                (request_id, revision_count, note, old_song_a_path, old_song_b_path, new_song_a_path, new_song_b_path)
@@ -193,6 +194,19 @@ def log_revision(request_id, revision_count, note, old_a=None, old_b=None, new_a
             (request_id, revision_count, note, old_a, old_b, new_a, new_b)
         )
         db.commit()
+    except sqlite3.OperationalError as e:
+        if 'no such table' in str(e):
+            # Schema drift: table missing. Recreate and retry once.
+            db.executescript(SCHEMA)
+            db.execute(
+                """INSERT INTO revision_history
+                   (request_id, revision_count, note, old_song_a_path, old_song_b_path, new_song_a_path, new_song_b_path)
+                   VALUES (?, ?, ?, ?, ?, ?, ?)""",
+                (request_id, revision_count, note, old_a, old_b, new_a, new_b)
+            )
+            db.commit()
+        else:
+            raise
 
 
 def list_revision_history(request_id):