fix(backup): use DB filename as backup prefix instead of hardcoded 'mc-webui'

Backup filenames now derive from the active DB stem (e.g. mc_9cebbd27.2026-03-24.db).
Listing and cleanup glob *.db so existing mc-webui.* backups remain visible.

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

app/database.py

@@ -1064,7 +1064,8 @@ class Database:
         backup_dir.mkdir(parents=True, exist_ok=True)
 
         date_str = datetime.now().strftime('%Y-%m-%d')
-        backup_path = backup_dir / f"mc-webui.{date_str}.db"
+        prefix = self.db_path.stem  # e.g. "mc_9cebbd27"
+        backup_path = backup_dir / f"{prefix}.{date_str}.db"
 
         source = sqlite3.connect(str(self.db_path))
         dest = sqlite3.connect(str(backup_path))
@@ -1084,7 +1085,7 @@ class Database:
             return []
 
         backups = []
-        for f in sorted(backup_dir.glob("mc-webui.*.db"), reverse=True):
+        for f in sorted(backup_dir.glob("*.db"), reverse=True):
             backups.append({
                 'filename': f.name,
                 'path': str(f),
@@ -1101,7 +1102,7 @@ class Database:
 
         cutoff = datetime.now() - timedelta(days=retention_days)
         removed = 0
-        for f in backup_dir.glob("mc-webui.*.db"):
+        for f in backup_dir.glob("*.db"):
             if datetime.fromtimestamp(f.stat().st_mtime) < cutoff:
                 f.unlink()
                 removed += 1

tests/test_database.py

@@ -392,7 +392,7 @@ class TestBackup:
         db.create_backup(backup_dir)
         backups = db.list_backups(backup_dir)
         assert len(backups) == 1
-        assert 'mc-webui.' in backups[0]['filename']
+        assert backups[0]['filename'].endswith('.db')
 
     def test_list_backups_empty_dir(self, db):
         with tempfile.TemporaryDirectory() as tmp: