Remove generated files from git tracking

- Add api/proto/generated/ to .gitignore (protobuf generated files)
- Add internal/ent/ and ent/ to .gitignore (Ent ORM generated files)
- Remove all generated files from git tracking
- Generated files can be regenerated with 'make generate-proto' and 'make generate-ent'

.gitignore

@@ -62,4 +62,13 @@ docs/.mkdocs_cache/
 
 
 # OS-specific
-Thumbs.db
+Thumbs.db
+
+.direnv/
+
+# Generated protobuf files
+api/proto/generated/
+
+# Generated Ent ORM files
+internal/ent/
+ent/