docs(openwebui-skills-manager): prioritize official marketplace install

- Update bilingual plugin README to use official marketplace as default install path.

- Keep manual paste installation as fallback and sync docs mirrors.

- Keep version unchanged at 0.2.1.

plugins/tools/openwebui-skills-manager/README.md

@@ -19,7 +19,7 @@ A standalone OpenWebUI Tool plugin to manage native **Workspace > Skills** for a
 ## How to Use
 
 1. Open OpenWebUI and go to **Workspace > Tools**.
-2. Create a new Tool and paste `openwebui_skills_manager.py`.
+2. Install **OpenWebUI Skills Manager Tool** from the official marketplace.
 3. Enable this tool for your model/chat.
 4. Ask the model to call tool operations, for example:
    - "List my skills"
@@ -28,6 +28,10 @@ A standalone OpenWebUI Tool plugin to manage native **Workspace > Skills** for a
    - "Update skill ..."
    - "Delete skill ..."
 
+### Manual Installation (Alternative)
+
+- Create a new Tool and paste `openwebui_skills_manager.py`.
+
 ## Example: Install Skills
 
 This tool can fetch and install skills directly from URLs (supporting GitHub tree/blob, raw markdown, and .zip/.tar archives).