docs(#743): address Kimi review — runtime count + support boundary

Address remaining review feedback on PR #743:

- Bump supported-runtime count 15 -> 16 across user-facing READMEs
  (docs/README.md + ja-JP/zh-CN translations) now that Kimi is added.
- Add an explicit support-boundary note in the Kimi CLI install section:
  the kimi --agent-file custom-agent contract targets legacy/Python
  kimi-cli; newer npm Kimi Code (@moonshot-ai/kimi-code) rejects
  --agent-file and consumes the same /skill:gsd-* skills via --skills-dir.
- Mirror the boundary in the changeset so release notes are unambiguous.

Historical ADR/changeset/INVENTORY references to '15 runtimes' are left
intact as point-in-time records.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.changeset/kimi-runtime-support.md

@@ -2,4 +2,4 @@
 type: Added
 pr: 743
 ---
-**Kimi CLI runtime support is now documented and installable** — users can install global GSD Agent Skills with `--kimi --global`, invoke them as `/skill:gsd-*`, and launch the generated custom agent explicitly with `kimi --agent-file`.
+**Kimi CLI runtime support is now documented and installable** — users can install global GSD Agent Skills with `--kimi --global`, invoke them as `/skill:gsd-*`, and launch the generated custom agent explicitly with `kimi --agent-file`. The custom-agent (`--agent-file`) surface targets the legacy/Python `kimi-cli` contract; newer Kimi Code (`@moonshot-ai/kimi-code`) consumes the same `/skill:gsd-*` skills via `--skills-dir` instead.

docs/README.md

@@ -15,7 +15,7 @@ Language versions: [English](README.md) · [Português (pt-BR)](pt-BR/README.md)
 
 ## How-to guides
 
-- [Install on your runtime](how-to/install-on-your-runtime.md) — runtime-specific install steps for all 15 supported runtimes
+- [Install on your runtime](how-to/install-on-your-runtime.md) — runtime-specific install steps for all 16 supported runtimes
 - [Install a minimal GSD and add skills later](how-to/install-minimal-and-add-skills.md) — install only the core skills, then grow the surface with profiles and `/gsd:surface`
 - [Discuss a phase](how-to/discuss-a-phase.md) — capture implementation decisions before planning begins
 - [Plan a phase](how-to/plan-a-phase.md) — run research, decompose work, and verify plan quality

docs/how-to/install-on-your-runtime.md

@@ -214,6 +214,8 @@ All registered hooks are managed by GSD and are removed cleanly on `--uninstall`
 
 ### Kimi CLI
 
+> **Support boundary — legacy `kimi-cli` vs Kimi Code.** This integration targets the legacy/Python `kimi-cli` custom-agent contract. The `kimi --agent-file <configRoot>/agents/gsd.yaml` launch shown below is accepted by `kimi-cli`. The newer npm Kimi Code (`@moonshot-ai/kimi-code`, e.g. `0.11.0`) does **not** accept `--agent-file`; it discovers skills through fixed skill roots and `--skills-dir`. The generated `/skill:gsd-*` skills work in both, but the custom-agent (`--agent-file`) surface is specific to legacy `kimi-cli`. For Kimi Code, point it at the installed skills root with `--skills-dir <configRoot>/skills` instead of using `--agent-file`.
+
 ```bash
 npx @opengsd/gsd-core@latest --kimi --global
 ```

docs/ja-JP/README.md

@@ -15,7 +15,7 @@
 
 ## How-to guides
 
-- [ランタイムへのインストール](how-to/install-on-your-runtime.md) — サポートされる全 15 ランタイムのランタイム別インストール手順
+- [ランタイムへのインストール](how-to/install-on-your-runtime.md) — サポートされる全 16 ランタイムのランタイム別インストール手順
 - [フェーズを議論する](how-to/discuss-a-phase.md) — 計画を始める前に実装上の決定事項を記録する
 - [フェーズを計画する](how-to/plan-a-phase.md) — リサーチを実行し、作業を分解し、計画の品質を検証する
 - [フェーズを実行する](how-to/execute-a-phase.md) — 新鮮なコンテキストのサブエージェントで並列ウェーブとして計画を実行する

docs/zh-CN/README.md

@@ -15,7 +15,7 @@
 
 ## How-to guides
 
-- [在你的运行时上安装](how-to/install-on-your-runtime.md) — 适用于全部 15 个受支持运行时的安装步骤
+- [在你的运行时上安装](how-to/install-on-your-runtime.md) — 适用于全部 16 个受支持运行时的安装步骤
 - [讨论一个阶段](how-to/discuss-a-phase.md) — 在规划开始前记录实现决策
 - [规划一个阶段](how-to/plan-a-phase.md) — 执行调研、分解工作并验证计划质量
 - [执行一个阶段](how-to/execute-a-phase.md) — 使用全新上下文的子代理以并行波次运行计划