Add trust-oriented provenance and recovery surfaces to Night Shift

[Fuiste]

Summary

• add night-shift provenance, night-shift doctor, and night-shift resume --explain
• persist per-run provenance.json and surface confidence posture in status, report, and dashboard payloads
• add deterministic confidence and recovery assessment logic for run inspection
• update docs and QA skill guidance to cover provenance, doctor, and the new trust signals
• add CLI and trust-surface tests for the new behavior

Testing

• gleam test

[Fuiste]

I found one blocking issue in the recovery path.

• src/night_shift/usecase/doctor.gleam:188-191 asks git.has_changes to log into filepath.join(task.worktree_path, ".night-shift-doctor.log"). But src/night_shift_shell.erl:57-65 truncates or creates the log file before the command runs. On an otherwise clean interrupted worktree, the probe itself therefore creates an untracked file inside the worktree, and git status --short --untracked-files=all reports dirty. That means doctor will classify clean running tasks as manual_attention instead of safe_to_resume, which defeats the main purpose of resume --explain / doctor. The log needs to live outside the inspected worktree (for example under the run's logs/ directory).

[Fuiste]

QA completed on the combined stack branch and the work has been superseded by #35.

What I validated:

• combined-branch end-to-end QA in the scratch repo
• intentional interruption followed by doctor, resume --explain, and resume
• successful verification, provenance/runtime artifacts, and delivery on the resumed run

Closing this PR in favor of the QAed combined branch.