IDE and runtime integration parity matrix

Provenance stamp: This issue was triaged on June 13, 2026 as part of the older-than-two-month GitHub issue triage exercise.

Source issues: #99, #185, #436, #496, #497, #499

## Summary

Plannotator now spans several agent runtimes and IDE surfaces. The backlog should track runtime support as a matrix instead of leaving separate old issues for each tool. Users need to know which combinations work, which are blocked by upstream behavior, and which need Plannotator work.

## What the source issues requested

- #99 reported that Claude Code hooks worked in the VS Code integrated terminal but not in the native Claude Code VS Code extension flow.
- #185 requested GitHub Copilot support, including manual import, markdown import, a VS Code bridge, or a generic import endpoint.
- #436 reported that Copilot CLI approval looped back into Plannotator instead of applying approval, with the maintainer noting upstream hook limitations.
- #496 requested that the Plannotator VS Code extension intercept plan reviews started by the official Claude Code VS Code extension instead of opening the external browser.
- #497 requested support for OpenAI Codex hooks so Codex users can get a plan review workflow.
- #499 requested OpenCode support inside the Plannotator VS Code extension.

## Triage determination

These are one integration-parity problem. Some runtime support has already shipped, but the support status is hard to reason about when each request lives separately. A matrix issue can separate shipped support, upstream blockers, and missing Plannotator work.

## Acceptance criteria

- Maintain a matrix for Claude CLI, Claude VS Code terminal, Claude VS Code extension, OpenCode CLI, OpenCode web or desktop, Copilot CLI, Copilot Chat or IDE, Codex skills, and Codex hooks.
- For each supported runtime, document whether plan review, code review, annotate, and last-message annotation work.
- For unsupported or partially supported runtimes, link the upstream blocker or the Plannotator implementation task.
- VS Code routing can consistently choose editor tab, external browser, or host-specific window where the runtime allows it.
- Copilot CLI support that has shipped is documented separately from Copilot Chat or IDE support that remains open.
- The old source issues can be closed once their runtime-specific requests are represented in the matrix.