Auto-ship mode + Ship button

[pechhe]

Parent

#38

What to build

Auto-ship mode and the one-click Ship action. A global default in Git settings, overridable per-thread from the Environment gear. When enabled, the Commit-or-push row becomes a single Ship button that drives the retained feature-done engine: commit → push → create PR → merge, spawning a resolver thread on merge conflict. When disabled (default), the manual flow (#41/#42) is used. The old always-on auto-publish behavior is fully retired — Ship only ever runs on an explicit click.

Acceptance criteria

• Git settings expose an Auto-ship global default; the Environment gear exposes a per-thread override.
• With Auto-ship on, the row renders as a single Ship button.
• Ship runs commit → push → PR → merge in one click using the feature-done engine.
• On merge conflict, Ship spawns a resolver thread (existing handoff-prompt behavior).
• With Auto-ship off, the manual flow is used; nothing auto-commits/merges/spawns without a click.
• live-lane test covers the Ship happy path; per-thread override behavior covered in core.

Blocked by

• Manual publish: commit + lazy branch + push #41
• Manual publish: Create PR #42