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/models.py

@@ -38,6 +38,8 @@ class Package(Base):
     project_id = Column(UUID(as_uuid=True), ForeignKey("projects.id", ondelete="CASCADE"), nullable=False)
     name = Column(String(255), nullable=False)
     description = Column(Text)
+    format = Column(String(50), default="generic", nullable=False)
+    platform = Column(String(50), default="any", nullable=False)
     created_at = Column(DateTime(timezone=True), default=datetime.utcnow)
     updated_at = Column(DateTime(timezone=True), default=datetime.utcnow, onupdate=datetime.utcnow)
 
@@ -49,6 +51,16 @@ class Package(Base):
     __table_args__ = (
         Index("idx_packages_project_id", "project_id"),
         Index("idx_packages_name", "name"),
+        Index("idx_packages_format", "format"),
+        Index("idx_packages_platform", "platform"),
+        CheckConstraint(
+            "format IN ('generic', 'npm', 'pypi', 'docker', 'deb', 'rpm', 'maven', 'nuget', 'helm')",
+            name="check_package_format"
+        ),
+        CheckConstraint(
+            "platform IN ('any', 'linux', 'darwin', 'windows', 'linux-amd64', 'linux-arm64', 'darwin-amd64', 'darwin-arm64', 'windows-amd64')",
+            name="check_package_platform"
+        ),
         {"extend_existing": True},
     )