Enrich repo commit events with full commit + numstat (no patch)

Goal#

Emit one stream event per commit that is a fully loaded commit summary: commit metadata plus per-file name-status + numstat (diffstat), without the unified patch/hunks.

Shape already exists as RPC repo.commitDetails / RepoCommitDetails + RepoCommitFileChange (apps/os/src/domains/repos/types.ts, line-diff.ts):

• oid, full message, author, timestamp, parents
• files[]: path, status (added | deleted | modified), additions, deletions, binary
• no separate “lines modified” count (git only has +/−)

Prefer reusing that type on the event rather than inventing a parallel shape.

Today#

• Cloudflare Artifacts push queue → repo/cloudflare-artifact-event-received → one repo/commit-completed per push tip with only { beforeCommitOid, branch, commitOid }.
• File awareness is derived later only for task markdown (repo/task-created|updated|deleted).
• Push payload may include commit headers (commits[], message, parents) but not file lists; commitsTruncated can omit commits on fat pushes.

Research notes (do not re-litigate without re-checking)#

• Artifacts Workers binding (env.ARTIFACTS): control plane + tokens only in current @cloudflare/workers-types — no numstat/diff.
• Artifacts HTTP control plane: log / commit / tree / blob / file / raw — still no diff/numstat/compare endpoint.
• Numstat must be computed by us (existing checkout + diffFileMaps, or tree/blob walk via object APIs if those stay available).

Design choices when we pick this up#

1. One event per commit in the push range (before…after), not one tip-only event per push.
2. Payload = commit metadata + numstat files (diffstat); large events OK; still no patch.
3. Walk incomplete commits[] via log when commitsTruncated.
4. Revisit whether task-specific events still need a separate path once generic file stats land on every commit event.

Explicitly deferred#

Not implementing now — captured so future work has context.