Enhance packages API with pagination, filtering, and metadata

Backend changes:
- Add format and platform columns to Package model with validation
- Add database migrations for new columns with indexes
- Create PackageDetailResponse schema with aggregated fields:
  - tag_count, artifact_count, total_size
  - latest_tag, latest_upload_at
  - recent_tags (last 5 tags)
- Update list_packages endpoint:
  - Add pagination (page, limit)
  - Add search by name/description
  - Add sort (name, created_at, updated_at) and order (asc, desc)
  - Add format and platform filters
  - Return aggregated metadata for each package
- Add GET /api/v1/project/{project}/packages/{package_name} endpoint
  - Returns single package with full metadata
  - Optional include_tags parameter for all tags
- Update create_package to accept format and platform

Frontend changes:
- Update Package type with format, platform, and optional metadata fields
- Update listPackages to handle paginated response

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/database.py

@@ -36,6 +36,32 @@ def _run_migrations():
             END IF;
         END $$;
         """,
+        # Add format column to packages table
+        """
+        DO $$
+        BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM information_schema.columns
+                WHERE table_name = 'packages' AND column_name = 'format'
+            ) THEN
+                ALTER TABLE packages ADD COLUMN format VARCHAR(50) DEFAULT 'generic' NOT NULL;
+                CREATE INDEX IF NOT EXISTS idx_packages_format ON packages(format);
+            END IF;
+        END $$;
+        """,
+        # Add platform column to packages table
+        """
+        DO $$
+        BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM information_schema.columns
+                WHERE table_name = 'packages' AND column_name = 'platform'
+            ) THEN
+                ALTER TABLE packages ADD COLUMN platform VARCHAR(50) DEFAULT 'any' NOT NULL;
+                CREATE INDEX IF NOT EXISTS idx_packages_platform ON packages(platform);
+            END IF;
+        END $$;
+        """,
     ]
 
     with engine.connect() as conn: