docs: make the documentation English-only

Removes the docs/zh tree and the tooling that maintained it: the translate-docs
and pre-changelog skills existed only to mirror and translate it, and gen-docs,
sync-changelog and write-tui each described a bilingual layout that no longer
exists. The VitePress config never wired a locale, so the Chinese pages were
built but unreachable from the site navigation.

The acp-adapter README pointed readers at two docs/zh paths for the capability
matrix and IDE setup; both now point at their English originals.

Author: elkaix

.agents/skills/gen-docs/SKILL.md

@@ -7,7 +7,7 @@ description: Update Pythinker Code CLI user documentation after meaningful code
 
 ## Overview
 
-This repository maintains bilingual user documentation under `docs/`. `docs/en/` and `docs/zh/` are mirrored pairs for most pages; update both in the same change. **Changelog is the exception** — English is the source, and Chinese is translated from English.
+This repository maintains English-only user documentation under `docs/`.
 
 Use this skill to update the corresponding documentation whenever the codebase has changes that affect product behavior or user experience.
 
@@ -17,10 +17,9 @@ For a **full pre-release audit** of all pages (detecting hallucinations and cove
 
 This skill depends on the following being in place. If any are missing, stop and report to the user before continuing:
 
-- `docs/` directory with `docs/zh/`, `docs/en/`, and `docs/.vitepress/config.ts` set up (VitePress site).
+- `docs/` directory with `docs/en/` and `docs/.vitepress/config.ts` set up (VitePress site).
 - `docs/AGENTS.md` style guide — defines source-of-truth rules, terminology table, typography, and writing style.
 - `docs/scripts/sync-changelog.mjs` — auto-syncs root `CHANGELOG.md` to `docs/en/release-notes/changelog.md`.
-- `translate-docs` skill in `.agents/skills/` — handles bilingual synchronization.
 
 ## Workflow
 
@@ -61,22 +60,14 @@ This skill depends on the following being in place. If any are missing, stop and
    - Customization (skills, agents, MCP, hooks, plugins, etc.)
    - Configuration (config files, env vars, providers, data locations)
    - Reference (CLI subcommands, slash commands, keyboard shortcuts)
-   - Release notes (`docs/zh/release-notes/breaking-changes.md` if a breaking change is involved)
-
-5. **Sync bilingual content**
-
-   Invoke the `translate-docs` skill. It will:
-
-   - Sync updated non-changelog pages between `docs/en/` and `docs/zh/`
-   - Translate the English changelog → Chinese under `docs/zh/release-notes/changelog.md`
+   - Release notes (`docs/en/release-notes/breaking-changes.md` if a breaking change is involved)
 
 ## Rules and conventions
 
-- **Locale sync**: Non-changelog pages stay mirrored between `docs/en/` and `docs/zh/`. Changelog flows English → Chinese.
-- **Terminology**: Use the term table in `docs/AGENTS.md` exactly. Do not invent new translations or use synonyms.
+- **Terminology**: Use the term table in `docs/AGENTS.md` exactly. Do not invent synonyms.
 - **Scope discipline**: Only update sections affected by the recent changes. Do not opportunistically rewrite unrelated docs.
 - **Public examples**: Never write real internal endpoints, key names, account names, or service names into docs. Use neutral placeholders such as `https://api.example.com/v1`, `https://registry.example.com/v1/models/api.json`, `example.test`, and `YOUR_API_KEY`.
-- **Breaking changes**: If any change is breaking, also update `docs/en/release-notes/breaking-changes.md` (under `## Unreleased`) with `**Affected**` + `**Migration**` subsections, and mirror it in `docs/zh/release-notes/breaking-changes.md`.
+- **Breaking changes**: If any change is breaking, also update `docs/en/release-notes/breaking-changes.md` (under `## Unreleased`) with `**Affected**` + `**Migration**` subsections.
 - **Do not edit auto-synced files**: `docs/en/release-notes/changelog.md` is regenerated by the sync script; any manual edit will be overwritten.
 
 ## Common mistakes