FE-1118: Reconcile host executor promotion

[kostandinang]

Summary

• Adds host promotion preflight and accepted apply tools for CODE mode.
• Applies promoted run patches to host files only; no commit/ref/index staging.

Verification

• npm run verify

[cursor]

PR Summary

High Risk
Introduces the first deliberate host worktree mutation path in execute mode; mistakes could corrupt the developer project tree, though acceptance gating, preflight reruns, and apply-check reduce blast radius.

Overview
Adds executor host promotion so verified run-local promotion commits can be inspected and applied to the host project worktree without leaving changes trapped in the run sandbox.

Core seam: new GitHostPromotionPort in execution-ports, executor helpers preflightHostPromotion / applyHostPromotion in host-promotion.ts, and app implementation git-host-promotion-port.ts that diffs in the run worktree and applies via git apply --check / git apply with stdin support added to command-runner.

CODE-mode tools: execute_host_promotion_preflight (read-only diff report) and execute_host_promotion_apply (requires acceptedCommitSha, reruns preflight, reports host_worktree_apply side effects). Wired through default Pi composition; admitted in EXECUTOR_ALLOWED_TOOL_NAMES; execute_status now derives ported tools from that list so text and details stay aligned.

Safety / hardening: apply fails closed on stale SHA, missing acceptance, or patch conflicts; no host commits, refs, branch switches, or index staging. Integration tests use real temp git repos for success and conflict paths; apply result type no longer includes impossible preflight_ready pass-through.

Plan/SPEC/invariant I56-L updated to document the new boundary; scope cards record the slice breakdown.

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[kostandinang]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• FE-1118: Reconcile host executor promotion #282 👈 (View in Graphite)
• FE-1112: Reconcile run-local executor promotion #279
• FE-1111: Reconcile executor agent runner #278
• FE-1109: Reconcile executor sandbox worktrees and test runner ports #275
• FE-1089: Reconcile executor with alpha branch #274
• next

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