fix(skills): preserve timeout failures and worker deadlines

[cheshirecode]

Timeouts could be reported as successful work or disappear behind fallback data. This change fixes four cases together:

• Sandbox dispatch requires exit zero and no process error, so an ETIMEDOUT result cannot become completed when a termination handler exits zero.
• Installation audit reports Git timeouts as unverified failures and finishes all initial observations before allowing repairs. Genuine non-Git source copies remain supported.
• Model discovery retains useful seed fallback with an explicit timeout, missing-CLI or failed-exit diagnostic; empty successful discovery remains distinct.
• Council declares execution deadlines separately from bounded tool waits, allows normal research time in foreground mode and settles the original worker before retrying within the remaining budget.

Validation: 12 installation-audit tests, 23 catalog tests, 11 dispatcher/manager unit tests and 14 static checks passed. Each of the three runtime regressions fails against the original source. Independent review found no blocking defects and checked the council deadline/settlement cases. The full Linux ARM64 suite passed 158 checks with zero failures; native loop-engineering passed all 99 tests. All five exact-head CI jobs passed: https://github.com/cheshirecode/dotfiles/actions/runs/34731165791.