feat: add Codex-native looperators agent loop

[ObservedObserver]

Summary

Adds the first production-shaped Codex-native looperators vertical slice: a bounded review-until-clean loop governed by typed MCP state, native Codex workers, and a protected localhost live graph.

This PR consolidates the full P0 → P1 development line and the later localhost-first simplification into one reviewed branch.

What changed

• adds a durable, versioned Agent Loop store and verified graph projection
• supports preview, start, typed implementer/reviewer reports, pause, resume, cancel, lap cap, and restart recovery
• replaces the default Hook-dependent design with cooperative role capabilities; the shipped Plugin has no Hooks
• adds an authenticated 127.0.0.1 review surface with SSE and same-origin controls
• extracts Desktop-derived ReactFlow graph components into @looperators/agent-graph-ui
• renders Governor, Implementer, Reviewer, relationships, inspector, loop state, issues, recovery, and timeline in the Codex right Browser
• records isolated install, real native-agent Gate A, and Codex Desktop Gate B evidence
• removes legacy inline rendering from the critical product path

Why

The earlier Hook and inline-first design required too much trust and was tightly coupled to Codex lifecycle behavior. The accepted architecture keeps Codex as the native task/subagent runtime, uses typed MCP as the loop authority, and treats the protected localhost Browser surface as the primary interactive UI.

User impact

A user can run one bounded review-until-clean loop inside a Codex task with a root Governor and native implementer/reviewer workers, inspect live authoritative state in the right Browser, and request pause/resume/cancel without installing default Hooks.

This is intentionally a focused Codex workflow, not a full replacement for the looperators Desktop orchestration runtime.

Validation

• npm run test:plugin-agent-loop-ui — 60 passed, 0 failed
• npm run lint — 0 errors; existing warnings only
• npm run build — passed
• git diff --check origin/main...HEAD — passed
• tracked-file credential pattern scan — no matches
• isolated local Plugin install — passed
• Gate A real root + implementer + reviewer issues-to-clean loop — passed
• Gate B fresh Codex Desktop task, right Browser graph, and UI pause round-trip — passed

Evidence

• internal_docs/plans/2026-08-02-codex-desktop-agent-loop-localhost-first.md
• internal_docs/experiments/artifacts/2026-08-02-codex-desktop-agent-loop-localhost-first/gate-a-real-loop.md
• internal_docs/experiments/artifacts/2026-08-02-codex-desktop-agent-loop-localhost-first/gate-b-desktop.md
• internal_docs/experiments/artifacts/2026-08-02-codex-desktop-agent-loop-localhost-first/desktop-interaction-parity.md

Known boundary

The default mode is cooperative. It cannot forcibly stop an in-flight native worker, force a worker to report, or force Codex to continue an ended turn. The Plugin currently requires a usable Node runtime and a new Codex task after installation or metadata updates.

Review status

• independent Codex review: all reported P1 findings fixed; follow-up found no remaining code P0/P1 after branch-history cleanup
• Grok Build review: root-only subagent authorization P1 fixed; follow-up found no remaining P0/P1
• CI rerun after the sanitized force-push: passed
• runtime prerequisite is Node.js 24.x; the Plugin does not yet bundle Node