chore: broaden .gitignore to stop committing runtime DB artifacts

Author: kulcsarrudolf

.gitignore

@@ -185,4 +185,20 @@ memory.db
 
 # Ignore Accounts database in capstone project
 6_mcp/accounts.db
-6_mcp/memory/*.db
+6_mcp/memory/*.db
+
+# Databases and vector store artifacts (ChromaDB, SQLite, etc.)
+# These files are runtime-generated and should not be committed.
+*.sqlite3
+*.sqlite
+*.db
+*.db-shm
+*.db-wal
+chroma.sqlite3
+data_level0.bin
+header.bin
+length.bin
+link_lists.bin
+
+# Generated audio/media artifacts from agent runs
+*.wav