Stop the tool-call repair recursing into itself

[davidmckayv]

What this changes

repairUnansweredToolCalls takes an id source so tests can make ids predictable:

newId: () => string = () => newId(),

Inside that default, newId resolves to the parameter, not the import on line 2. The default
calls itself until the stack goes. Introduced by #62.

It hangs exactly when the function does its job. The parameter is only invoked on the repair branch,
reached when there is an unanswered tool call, and the one real caller
(channel-chat.tsx L228) omits the argument. Every existing test passes its own ids, so no test ever
ran the default.

Renamed the parameter so it cannot shadow the import, and added a test that calls it the way the
real caller does.

Found by @guidovizoso. Biome had flagged it too, as noUnusedImports on line 2, which I waved
through as a warning when I made the change.

Where it runs

• New state that outlives a request? None. A pure function over a message array.
• What happens on the second replica? Identical; nothing is held.
• Anything serialised? N/A.
• Anything fanned out to a browser? No.
• New listener, port, or schedule? No.

Boundary and audit

• N/A. No gateway, policy, or audit path touched.

Changelog

• No entry. It fixes an unreleased defect introduced by Run OpenBot as one container, and give a Bot a shell #62, which has not shipped in a release.

Proof

The new test fails on the old code by hanging rather than by asserting, which is the honest
reproduction. 745 tests pass, biome check clean on both files, typecheck clean.