test(cli): pin the five cluster-driver diagnosis branches at boot, silence included (#15381)

* test(cli): pin the five cluster-driver diagnosis branches at boot

WIP: first full draft of the boot-level suite for #14054.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D47qPfEWVPmhguWgBZCi5N

* test(cli): record the ablation that reds each cluster-diagnosis pin

The two mutations, what each one turns red, and why no rebuild is involved
(the harness runs `serve.ts` from source through tsx).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D47qPfEWVPmhguWgBZCi5N

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Co-authored-by: Claude <noreply@anthropic.com>

Author: os-litant