feat(dev): re-sync installed dev hosts on epoch swap behind the stable proxy (#179 stage 2)

[ScriptedAlchemy]

Summary

Stage 2 of #179: agent-bundle dev --install-host <claude|codex|cursor> (repeatable) installs the developed plugin into real hosts as a marked DEV VARIANT and re-syncs skills/hooks/mcp-apps/manifests into the installed locations on every successful epoch swap — hosts pick up changes without reinstall. Hooks are spawned per event, so they adopt the new epoch on the next event; the MCP surface stays live through the stage-1 proxy (#339).

• Dev install: first successful epoch installs through the ordinary installBundle path (real claude/codex plugin CLIs, Cursor copy), with the MCP document rewritten to the stable proxy command and a .agent-bundle-dev.json marker (schemaVersion 1, projectRoot, host, epochId).
• Stable, host-spawnable proxy command (single seam dev/dev-proxy-command.ts): process.execPath + the framework's own resolved CLI entry (package-root walk → declared bin → existence check; no PATH assumption) + dev proxy --root <project> --server <name> --target <host>. Never rewritten to an epoch path on swap (byte-identical mcp document pinned in tests).
• Re-sync on artifact.available: each epoch copies into an immutable generation under .agent-bundle-dev/generations/<epochId>; top-level directories switch by atomic symlink (junction on Windows) rename, top-level files by atomic sibling rename — a host never reads a torn tree (the first swap after install renames the real directory aside before the pointer lands). Failed publish rolls back to the previous generation and emits AB7202 on a new epoch-scoped dev.host.sync project event; failed builds emit nothing (last-good stays). Generations pruned to {current, previous}.
• Claude/Codex re-sync writes the host-owned cache directly — no host CLI invocation per epoch (pinned: command-runner call count unchanged across a swap).
• Workbench wire mirror updated (log-client.ts devLogKinds) so dev.host.sync / dev.host.sync.diagnostic frames don't hard-fail the Logs page with AB8093; project SSE is unaffected (named events, no listener).
• Shutdown leaves the dev install in place: skills/hooks remain, and the proxy fails closed (AB8025) until that project's dev server runs again.

Tests

tests/dev-host-install.test.ts (integration pool + test:host-install script):

• Cursor (unconditional): dev-variant layout + marker; epoch swap re-points skills/hooks atomically; mcp document byte-identical; failed build → no change; failed re-sync → previous generation restored + AB7202 event; generation pruning to {current, previous}.
• Real DevCoordinator + EpochStore end-to-end: skill + hook edits propagate into the isolated Cursor install after a real rebuild; broken source leaves the install and marker untouched.
• Claude / Codex (binary-gated, honest skips): real host-CLI install into isolated homes, then a re-sync into the host-owned cache with zero further host CLI calls, marker advanced, skills/hooks changed, mcp document unchanged.
• Spawn proofs (all three hosts): the exact emitted command/args spawn with no dev server running and fail closed with exit 1 + [AB8025] — proving a real host could spawn it without PATH assumptions.
• packages/workbench/tests/log-client.test.ts covers the new kinds.

Reviewer fix included: dev-host-install.test.ts was initially picked up by the "build-free, process-free" unit pool; it is now classified in integrationTestFiles and rides test:host-install.

Gates (local, rebased)

• pnpm build / pnpm typecheck / pnpm lint (0/0) — pass
• pnpm test:unit 2633 passed; only residue is the two known timing flakes under machine load (mcp-probe-service teardown, dispatcher deadline) — 34/34 in isolated rerun
• pnpm test:route-unit 24/24 · pnpm test:projection 59/59
• dev-host-install (integration config) 7/7 · pnpm test:host-install 16/16 with 0 skips (real claude + codex lanes executed)
• workbench log-client 15/15

Part of #179 (stage 2 of 4). Changeset: minor.

[changeset-bot]

🦋 Changeset detected

Latest commit: 77ca3a9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
agent-bundle	Minor

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-03T00:24:09.759504Z	77ca3a9	PR opened

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