Make reviewer handoff sequential and expose review links

[DevDeepakBhattarai]

Summary

• replace the model-facing generic delegation workflow with one sequential, read-only reviewer handoff while retaining the existing local job registry underneath
• add list_reviewers and return/display each review's exact ChatGPT conversation URL from start_reviewer, the reviewer MCP App, and the RALPH Reviews UI
• pause RALPH continuation while a review is unfinished, preserve explicit engineering checkpoints, and keep explicit user-created threads separate from reviewer jobs
• migrate legacy report state from subagents/ to reviewer-named reviews/ storage without deleting the legacy files
• add reviewer lifecycle, migration, Thread Sync, and support-popup regression coverage

Verification

• pnpm type
• pnpm thread-sync-test
• pnpm support-ui-test
• git diff --check

All tests ran from the clean stacked worktree without starting the normal Local Codex server. The support popup test uses an isolated headless Chrome instance with local fixtures.

Stack

This PR is intentionally based on fix/thread-sync-executor-liveness / PR #1 so the reviewer workflow can rely on the executor-liveness fix without duplicating it in this diff. It can be retargeted to master after PR #1 lands.

[chatgpt-codex-connector]

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