- Add new `/api/s2a/profiles` endpoint supporting GET, POST, DELETE operations
- Create `s2a_profiles` database table with fields for API configuration, concurrency, priority, group IDs, and proxy settings
- Implement database methods: `GetS2AProfiles()`, `AddS2AProfile()`, `DeleteS2AProfile()`
- Add S2AProfile struct to database models with JSON serialization support
- Implement profile management UI in S2AConfig page with save, load, and delete functionality
- Add profile list display with ability to apply saved configurations
- Add S2AProfile type definition to frontend types
- Enable users to save and reuse S2A configurations as presets for faster setup
- Aggregate total_registered and total_added_to_s2a from batch_team_results table
- Calculate success_rate based on actual S2A additions vs total owners
- Compute duration_seconds from started_at and finished_at timestamps
- Improve stuck batch run recovery by restoring accurate metrics instead of zeroing them out
- Add CleanupStuckProcessingOwners database method to reset owners stuck in processing status back to valid state
- Call cleanup routine on application startup to recover from previous abnormal exits
- Call cleanup routine after batch processing completes to ensure no orphaned processing states remain
- Add markOwnerResult calls in processSingleTeam when team invitations are full to properly track owner status
- Prevents owners from being permanently stuck in processing state due to unexpected shutdowns or errors
