Add pagination and search to projects API

- Add PaginatedResponse and PaginationMeta schemas
- Update GET /api/v1/projects to support:
  - page param (default: 1)
  - limit param (default: 20, max: 100)
  - search param (case-insensitive name search)
- Response includes pagination metadata (page, limit, total, total_pages)
- Add Python cache files to gitignore

.gitignore

@@ -1,3 +1,11 @@
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+.Python
+*.egg-info/
+.eggs/
+
 # Binaries
 /bin/
 *.exe