fix(skills): preserve released import skill selector

Released Chinese and Traditional Chinese clients install chatlab-import-cn from the default branch. Keep a deprecated, self-contained English entry so those commands continue to work, and document migration to the unified skill.

docs/cn/usage/how-to-import.md

@@ -26,7 +26,7 @@ npm install -g chatlab-cli
 npx skills add ChatLab/ChatLab --skill chatlab-import -g
 ```
 
-各语言共用同一个技能，可以直接用中文提出需求。曾安装 `chatlab-import-cn` 时，请先保留自定义改动，再安装上面的统一版本，并通过原安装工具移除旧入口，避免重复显示。
+各语言共用同一个技能，可以直接用中文提出需求。`chatlab-import-cn` 作为已弃用的兼容入口保留，确保 ChatLab v0.31.1 至 v0.37.1 首页中的旧安装命令继续有效；其正文也使用英文，回答遵循用户语言。曾安装旧入口时，请先保留自定义改动，再安装上面的统一版本，并通过原安装工具移除旧入口，避免重复显示。
 
 然后直接告诉 Agent：
 

docs/en/usage/how-to-import.md

@@ -26,7 +26,7 @@ npm install -g chatlab-cli
 npx skills add ChatLab/ChatLab --skill chatlab-import -g
 ```
 
-The same skill works across languages; ask in your preferred language.
+The same skill works across languages; ask in your preferred language. The deprecated `chatlab-import-cn` entry remains available for installation commands shown in ChatLab v0.31.1 through v0.37.1. Its instructions are also in English, and responses follow your language. If you already installed it, preserve any custom changes, install the unified skill above, then remove the old entry with your original installation tool to avoid duplicates.
 
 Then ask the agent:
 

docs/tw/usage/how-to-import.md

@@ -26,7 +26,7 @@ npm install -g chatlab-cli
 npx skills add ChatLab/ChatLab --skill chatlab-import -g
 ```
 
-各語言共用同一個技能，可以直接用繁體中文提出需求。曾安裝 `chatlab-import-cn` 時，請先保留自訂修改，再安裝上面的統一版本，並透過原安裝工具移除舊入口，避免重複顯示。
+各語言共用同一個技能，可以直接用繁體中文提出需求。`chatlab-import-cn` 作為已棄用的相容入口保留，確保 ChatLab v0.31.1 至 v0.37.1 首頁中的舊安裝命令繼續有效；其正文也使用英文，回覆遵循使用者語言。曾安裝舊入口時，請先保留自訂修改，再安裝上面的統一版本，並透過原安裝工具移除舊入口，避免重複顯示。
 
 然後直接告訴 Agent：
 

skills/chatlab-import-cn/SKILL.md

@@ -0,0 +1,59 @@
+---
+name: chatlab-import-cn
+description: >-
+  Deprecated compatibility entry for local imports from released ChatLab clients; prefer chatlab-import for new installs. 旧版 ChatLab 导入命令的兼容入口，新安装请使用 chatlab-import。
+---
+
+# ChatLab Import (Legacy Compatibility)
+
+This deprecated entry preserves installation commands shipped in ChatLab v0.31.1 through v0.37.1. It includes the complete import workflow below and does not require `chatlab-import` to be installed. For new installations, use `npx skills add ChatLab/ChatLab --skill chatlab-import -g`; migrating is not required to complete an import.
+
+Import local chat exports through the `clb` CLI. Always preview the exact write. Treat an explicit request to import as authorization to continue after a successful preview; do not ask for a second confirmation.
+
+Follow the user's requested response language; otherwise use the conversation language, preserving the user's Chinese variant when applicable. Keep commands, field names, IDs, and evidence markers unchanged.
+
+For analysis of imported records, use `chatlab-analyze` when available. For an unsupported source, use `chatlab-convert` when available; neither skill is required for a supported import.
+
+## Workflow
+
+1. Check the CLI and resolve one exact file path:
+
+```bash
+clb --help
+```
+
+If the CLI is missing, tell the user to install it with `npm install -g chatlab-cli`. Do not install software without approval. Reuse the user's specified file and target. Ask only if the path remains ambiguous, and quote it in every command.
+
+2. Preview the import without writing:
+
+```bash
+clb import "/absolute/path/to/chat-export.json" --dry-run --json
+```
+
+If the user selected an existing session, include `--session-id <session-id>` in both preview and import.
+
+3. Summarize only the plan: create or update mode, target session ID, scanned messages, new messages, duplicates, and match method or create reason. Never quote message bodies.
+
+4. Require `ok: true`, then read the plan from `data` and decide:
+
+- If the user asked only to preview or inspect, stop without writing.
+- If `importMode` is `incremental` and `newMessageCount` is `0`, report that the session is already up to date and stop.
+- If `importMode` is `incremental` and there are new messages, continue automatically without another confirmation.
+- If `importMode` is `created`, continue automatically. When `createReason` is `ambiguous`, preserve existing sessions by creating a new one and explain this choice in the final result.
+- If the result does not identify a safe action, stop and explain what is missing.
+
+5. When the decision permits writing, run the same command without `--dry-run`, keeping the file, target, and format unchanged:
+
+```bash
+clb import "/absolute/path/to/chat-export.json" --json
+```
+
+Report the resulting session ID, import mode, new-message count, and duplicate count from the final JSON envelope.
+
+## Guardrails
+
+- Never skip the preview, edit ChatLab databases directly, or delete or merge sessions.
+- Never reveal a full chat export or message bodies.
+- Never invent a file path, parser format, or session ID.
+- Follow `error.hint` only when the correction is unambiguous.
+- For `FILE_NOT_FOUND` or `INVALID_SESSION_ID`, resolve from available context or request the correct value. For `UNRECOGNIZED_FORMAT`, inspect `clb formats`. For `IMPORT_IN_PROGRESS`, retry once after the active import finishes; if still blocked, report it instead of polling indefinitely.