[Bug]: t3_queue reorder can't move a message to the end: the advertised schema drops `null` from `beforeRunId`#30303

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Queue two or more messages on a thread.
2. From an agent, call the MCP tool t3_queue with action: "reorder" and beforeRunId: null, as its description says ("reorder: before beforeRunId, or to the end with null").
3. Look at the input schema T3 advertises for t3_queue.

Expected behavior

beforeRunId is advertised as string or null, and null moves the message to the end of the queue.

Actual behavior

The advertised schema has beforeRunId: { "type": "string" }. QueueTool declares beforeRunId: Schema.optional(Schema.NullOr(RunId)) (apps/server/src/mcp/toolkits/thread/tools.ts:99), and compact in apps/server/src/mcp/advertisedJsonSchema.ts (#25423) drops the null branch of optional properties. So an agent that follows the schema can't send null. Ours sent the string "null", which the server read as a run id and answered "Failed to reorder". The handler still treats null as "to the end", so only the advertised schema is wrong. advertisedJsonSchema.test.ts covers a required NullOr field, not this optional one.

Possible fix: keep the null branch when null has a meaning (here beforeRunId), and add this shape to advertisedJsonSchema.test.ts.

Impact

Major degradation or frequent failure

Version or commit

main @ a760f374f

Environment

No response

Logs or stack traces

Screenshots, recordings, or supporting files

No response

Workaround

Move each message queued after it to before it, one by one.