docs(mcp): fix persistent profile directory name in README

The documentation listed `mcp-{channel}-profile` as the default
profile directory, but the code generates `mcp-{channel}-{hash}`
where the hash is derived from the MCP client's workspace root.

Author: lennondotw

README.md

@@ -413,15 +413,17 @@ Persistent profile is located at the following locations and you can override it
 
 ```bash
 # Windows
-%USERPROFILE%\AppData\Local\ms-playwright\mcp-{channel}-profile
+%USERPROFILE%\AppData\Local\ms-playwright\mcp-{channel}-{workspace-hash}
 
 # macOS
-- ~/Library/Caches/ms-playwright/mcp-{channel}-profile
+- ~/Library/Caches/ms-playwright/mcp-{channel}-{workspace-hash}
 
 # Linux
-- ~/.cache/ms-playwright/mcp-{channel}-profile
+- ~/.cache/ms-playwright/mcp-{channel}-{workspace-hash}
 ```
 
+`{workspace-hash}` is derived from the MCP client's workspace root, so different projects get separate profiles automatically.
+
 **Isolated**
 
 In the isolated mode, each session is started in the isolated profile. Every time you ask MCP to close the browser,