fix(backfill): the byo-stamp scan read config as an object; it is a Map

[lilyshen0722]

The dry run caught this, which is the only reason it's a commit and not an incident.

What happened

config is { type: Map, of: Mixed } (AgentRegistry.ts:235), so on a live Mongoose document config.runtime is undefined. The scan omitted .lean(), so every row filtered out on a property that cannot exist. Against production:

installs scanned:      545
already stamped:       0     ← two seats were demonstrably stamped
push webhooks skipped: 0
candidates to stamp:   0     ← ~200 are candidates

With --apply it would have written nothing and printed success — the migration-reports-success-and-writes-nothing failure this file already warned about, arriving through a different door than the one guarded.

The actual lesson

This is the same Map-vs-object defect just fixed in the install intro (#947). I wrote this script before diagnosing that one and never came back to it. The fix got applied where the bug was found rather than everywhere the shape is read — which is how one root cause ships twice.

The fix

• Scan uses .lean(), plus a runtimeOf reader that handles both shapes, so a caller passing a live document degrades to a correct read instead of a silently empty one.
• Write switched to updateOne with a dotted $set. The rows are lean so there's no document to save; a dotted path writes one key without rewriting the whole config, so a concurrent install touching another key isn't clobbered; and it sidesteps Mixed-path dirty tracking entirely.
• The counter reports what the DB says it modified, not what the loop intended — the exact gap that let the first version look successful.

Next

Re-run the dry run after this merges. Expect ~200 candidates, and the two already-stamped seats to show under already stamped rather than 0. Only then --apply.

🤖 Generated with Claude Code

https://claude.ai/code/session_01XeUH4HVDsDHYPsHJthXjB8