The skeptic: advisory pre-ship review stage

Part of #16, the first soul with a real job. The current ship flow is checks green, six-digit code, tired human eyes. Nobody with taste reads the diff except the human.

• New stage between ALL GREEN and the ship code: the skeptic reads the integration diff armed with .thrawn/lessons.md (#18) and its own convictions
• Advisory, never blocking: the verdict lands in state.json and renders on the status board next to the ship code; shipping still happens on the human's say-so
• Journal: the skeptic appends what it approved and flagged per run; when something it approved later breaks, that goes in its journal so its own miss history weighs on future reviews
• Soul file souls/skeptic.md with genuinely opposed defaults to the builder: it tries to kill the change, not to bless it

Depends on #19 (mechanism) and benefits from #18 (lessons). Lands after phase 2 of #14 concludes so the trial's ship flow stays constant.

Agent brief (phase 2 constraint)

May be attempted during phase 2 ONLY behind a flag: add skeptic = "" to [personas]-adjacent config ([thrawn] skeptic_enabled = false or an empty skeptic mapping meaning off), and the new review stage between ALL GREEN and the ship code must be a no-op unless enabled. Write souls/skeptic.md per souls/README.md. The verdict lands in state.json and renders on the board when enabled. Advisory only, never blocking. Acceptance: make test and make lint green; a run with the skeptic disabled behaves byte-identically to today.

Read souls/README.md and trace the existing ship flow around ALL GREEN, the ship code, state.json, and the status board. Add the phase-2-disabled configuration and souls/skeptic.md, then verify enabled runs record and render an advisory verdict while disabled runs remain byte-identical; finish with make test and make lint.