chore: ignore embedded desktop build artifacts

The desktop/ subproject (added next) carries its own node_modules,
dist, and Cargo target dirs once built. Ignore them from the metapi
root so the 6.5G+ of generated output never enters the repo.

.gitignore

@@ -31,3 +31,12 @@ boosapi.db-shm
 boosapi.db-wal
 .tours/
 bun.lock
+
+# Embedded desktop subproject (BoosAPI Desktop) — generated artifacts only.
+# Source lives in desktop/; these are build outputs that must never be tracked.
+desktop/node_modules/
+desktop/dist/
+desktop/target/
+desktop/src-tauri/target/
+desktop/src-tauri/gen/schemas/
+desktop/website/node_modules/