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

backend/app/schemas.py

@@ -1,8 +1,23 @@
 from datetime import datetime
-from typing import Optional, List
+from typing import Optional, List, Generic, TypeVar
 from pydantic import BaseModel
 from uuid import UUID
 
+T = TypeVar("T")
+
+
+# Pagination schemas
+class PaginationMeta(BaseModel):
+    page: int
+    limit: int
+    total: int
+    total_pages: int
+
+
+class PaginatedResponse(BaseModel, Generic[T]):
+    items: List[T]
+    pagination: PaginationMeta
+
 
 # Project schemas
 class ProjectCreate(BaseModel):