[2/N] [List API] feat(context): add immutable request admission store

[albertywu]

Summary

Adds immutable request context when request is admitted.

Test Plan

✅ make fmt && make build && make test && make check-mocks && make e2e-test

Stack

1. [1/N] [List API] docs(list): define request context read model #310
2. @ [2/N] [List API] feat(context): add immutable request admission store #302
3. [3/N] [List API] feat(summary): project request logs from admission context #303
4. [4/N] [List API] feat(gateway): expose List API from request summaries #304
5. [5/N] [List API] test(e2e): cover gateway List API #305
6. [6/N] [List API] docs(service): document gateway List API read model #306

[Copilot]

Pull request overview

This PR extends SubmitQueue’s append-only request log so each log row persists immutable queue and change metadata, enabling future queue-scoped read models while keeping backward-compatible fallbacks via the existing request ID format.

Changes:

• Add queue and change_uri columns to the request_log MySQL schema and persist/load them in the MySQL request-log store.
• Extend entity.RequestLog serialization with Queue and ChangeURIs, including defaulting/back-compat behavior on deserialize.
• Add helper functions for extracting queue from request ID (QueueFromRequestID) and validating known request statuses (IsKnownRequestStatus), plus a small MySQL store unit test and Bazel test target.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
submitqueue/extension/storage/mysql/schema/request_log.sql	Adds queue + change metadata columns to the request_log table schema.
submitqueue/extension/storage/mysql/request_log_store.go	Serializes/deserializes new fields and validates queue presence on insert.
submitqueue/extension/storage/mysql/request_log_store_test.go	Adds a unit test for rejecting inserts when queue can’t be derived.
submitqueue/extension/storage/mysql/BUILD.bazel	Adds a go_test target for the new MySQL unit test.
submitqueue/entity/request_log.go	Adds new RequestLog fields, defaults/back-compat, and new helper functions.
submitqueue/entity/request_log_test.go	Updates serialization tests and adds coverage for QueueFromRequestID.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

submitqueue/extension/storage/mysql/request_log_store.go:67

• RequestLog.Metadata is documented as an “empty map if no metadata”, but Insert will marshal a nil map as JSON null, which then round-trips back to a nil map on List. Normalize log.Metadata to an empty map before marshaling so DB rows and readers preserve the non-nil invariant used by RequestLogFromBytes.

	metadataJSON, err := json.Marshal(log.Metadata)
	if err != nil {
		return fmt.Errorf("failed to marshal metadata for request log request_id=%s: %w", log.RequestID, err)
	}

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 13 changed files in this pull request and generated 2 comments.

Files not reviewed (2)

• submitqueue/extension/storage/mock/request_context_store_mock.go: Generated file
• submitqueue/extension/storage/mock/storage_mock.go: Generated file

[albertywu]

Closing in favor of new design in #314