Remove database files from version control and update .gitignore

- Remove numerology.db from Git tracking (keep local file)
- Add comprehensive database file patterns to .gitignore
- Include *.db, *.sqlite, *.sqlite3 patterns
- Prevent future database files from being committed

.gitignore

@@ -48,5 +48,10 @@ temp/
 *.njsproj
 *.sln
 *.sw?
+# Database files
+numerology.db
 numerology.db-shm
 numerology.db-wal
+*.db
+*.sqlite
+*.sqlite3