chore: add SQLite WAL mode files to .gitignore

Add *.db-shm, *.db-wal, and *.db-journal patterns to ignore
SQLite Write-Ahead Logging temporary files.

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -113,6 +113,9 @@ $RECYCLE.BIN/
 *.sqlite
 *.sqlite3
 *.db
+*.db-shm
+*.db-wal
+*.db-journal
 *.sql
 
 # Log files