feat: send sync report to Quartermaster

[cebarks]

Summary

• Adds SendReport() to SyncEngine that POSTs sync outcome to Quartermaster's /quma/convoy/report endpoint after every sync
• Reports profile AID (from RequestHandler.SessionId), result (up_to_date/updated/failed), installed mod snapshot, client version, and error details on failure
• Uses RequestHandler.PostJson so the request routes through SPT's authenticated HTTP channel
• Fire-and-forget with try/catch — a failed report never blocks or breaks sync
• Updated SPT stubs with SessionId and PostJson for CI compilation

How it works

Every exit path in RunSync() now calls SendReport():

• Catalog unchanged (304) → up_to_date with current mod list
• All checksums match → up_to_date with current mod list
• Mods downloaded/removed → updated with new mod list
• Hash verification failed → failed with error message
• Unhandled exception → failed with exception message

The server endpoint already exists and displays reports on the Convoy status dashboard tab.

Test plan

• Build succeeds with 0 warnings, 0 errors
• Deploy to SPT client, verify Sync report sent: up_to_date appears in BepInEx log on clean sync
• Force a mod update, verify Sync report sent: updated appears
• Check Quartermaster Convoy > Status tab shows the client's report

🤖 Generated with Claude Code