Remove build artifacts and add .gitignore

- Delete all compiled .js, .js.map, .d.ts, and .d.ts.map files
- Keep fix-imports.js as it's a source script
- Add .gitignore to prevent future build artifacts from being committed

Author: zephraph

src/clients/deno/.gitignore

@@ -0,0 +1,11 @@
+# Build artifacts
+*.js
+*.js.map
+*.d.ts
+*.d.ts.map
+
+# Keep specific files
+!fix-imports.js
+
+# Dependencies
+node_modules/