[Bug] Uninstall cleanup query uses wrong column name for installation ID

[jonathanchang31]

Summary

installation.deleted cleanup uses a raw where clause with installationId instead of DB column installation_id:

.where("installationId = :id", { id: String(installationId) })

Because this is a raw SQL fragment, entity property names are not guaranteed to map to snake_case DB columns. Cleanup may fail to match rows.

Impact

High / state integrity:

• Repos may remain linked to removed installation after uninstall.
• registered/installation state can drift from GitHub app reality.
• Future lifecycle events/backfill decisions can run against stale installation linkage.

Repro (conceptual)

1. Install app for repos (rows have installation_id set).
2. Trigger installation.deleted.
3. Observe cleanup query uses installationId in raw where fragment.
4. Rows may not be cleared due to column-name mismatch.

Expected behavior

Uninstall cleanup should reliably clear all repos by installation_id and set registered=false.

Suggested fix direction

• Use DB column name in raw fragment:
• where("installation_id = :id", { id: ... })
• Or use object-based criteria API to avoid column-name mismatch risk.
• Add regression test for uninstall cleanup.