docs(skills): add profile-specific installation documentation

Update both English and Chinese README files with:
- CLI examples for --profile option
- Reorganized manual creation as alternative method

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/agent/skills/README.md

@@ -205,7 +205,17 @@ On first run, bundled skills are automatically copied to the managed directory (
 
 ### Adding Profile-Specific Skills
 
-Profile-specific skills are not installed via CLI. Instead, manually create them in the profile's skills directory:
+You can install skills directly to a profile using the `--profile` option:
+
+```bash
+# Install skill to a specific profile
+multica skills add owner/repo --profile my-agent
+
+# Install with force overwrite
+multica skills add owner/repo/skill-name --profile my-agent --force
+```
+
+Alternatively, create them manually:
 
 ```bash
 # Create profile skills directory

src/agent/skills/README.zh-CN.md

@@ -205,7 +205,17 @@ Skills 从两个来源加载，优先级从低到高：
 
 ### 添加 Profile 专属 Skills
 
-Profile 专属 skills 不通过 CLI 安装，需要手动创建在 profile 的 skills 目录中：
+可以使用 `--profile` 选项直接安装 skills 到特定 profile：
+
+```bash
+# 安装 skill 到特定 profile
+multica skills add owner/repo --profile my-agent
+
+# 强制覆盖安装
+multica skills add owner/repo/skill-name --profile my-agent --force
+```
+
+也可以手动创建：
 
 ```bash
 # 创建 profile skills 目录