* feat(skill): add UPLOADED status for PRIVATE skill lifecycle
## Summary
- Add UPLOADED status for PRIVATE skills after security scan passes
- PRIVATE skill owners can test before confirming publish or submitting for review
- Rerelease now follows visibility rules (PRIVATE→UPLOADED, PUBLIC→PENDING_REVIEW)
- Auto-withdraw changes status to UPLOADED (not DRAFT) to keep versions visible
## Changes
- SkillVersionStatus: Add UPLOADED enum value
- SkillPublishService: PRIVATE skills go to UPLOADED after scan
- SecurityScanService: Visibility-based status transition after scan
- SkillGovernanceService: Withdraw→UPLOADED, delete allows UPLOADED
- SkillQueryService: Include UPLOADED in version list filters
- SkillReviewSubmitService: New service for submit-review and confirm-publish
- SkillLifecycleController: Add submit-review and confirm-publish endpoints
- Frontend: Add buttons, dialogs, and hooks for new operations
## Workflow
- PRIVATE: Publish → SCANNING → UPLOADED → confirm-publish → PUBLISHED
- PUBLIC: Publish → SCANNING → PENDING_REVIEW → PUBLISHED
* feat(review): add backward compatibility for DRAFT status
Support both DRAFT (legacy) and UPLOADED (new flow) status in:
- SkillReviewSubmitService.submitForReview
- SkillReviewSubmitService.confirmPublish
- ReviewService.submitReview (both overloads)
This ensures existing data with DRAFT status continues to work
with the new visibility-based workflow introduced in OSS-02.
