#1426 Post-0.64 batch 1: runner completions, build-server fixes, restart survival, self-hosted CI

Post-0.64 batch 1, run once in full on our own runners (Tests run 43007003726 green on all three platforms at this head).

What lands:

• Runner background completions no longer replay to every reconnecting route (the RC10 card fix), and Broca's project-free late_results are served again.
• Build-server jobs: bash_kill cancels queued and running jobs on the server; memory kills say whose limit; return_paths reserves the large-return cap.
• Read-only tools skip the undo-backup lock; aft_search waits up to 8 s for a new project's text index.
• Restart survival: Broca's runner_restart yield holds worker bash calls and settles their real results (schema-29 carrier custody); yield admission is no longer refused mid-admission.
• Stall watchdog: a parked or paging frame loop defers its restart (host starvation), with a 5-minute ceiling for real wedges.
• Configure warnings resolve each folder once for Biome instead of every file.
• Folder of repositories: grep and glob search a loading repository directly, and gaps lead the reply (#1423).
• gh --jq failures with empty stderr report the exit status.
• Config watcher re-checks once after arming a watch, so an edit made while it starts is not missed.
• CI: macOS and Windows test lanes and release builds run on our self-hosted runners; gate logs print on failure there.
• Test fixes for the new runners (macOS first-exec warm-ups, Windows paths, conformance kit 0.15.6).

Release-note fragments are under .alfonso/release-notes/next/.