docs: update README and add note for JSON handling in testMatchCodeRuleTool

Author: nedithgar

README.md

@@ -50,7 +50,7 @@ Launch the MCP server over stdio:
 ```bash
 swift run ast-grep-mcp-swift --config /absolute/path/to/sgconfig.yaml
 swift run ast-grep-mcp-swift --verbose --config /absolute/path/to/sgconfig.yaml  # verbose debug logs to stderr
-swift run ast-grep-mcp-swift --version  # or -v, print version information
+swift run ast-grep-mcp-swift --version  # print version information
 ```
 
 You can omit `--config` if you rely on defaults or the `AST_GREP_CONFIG` environment variable.

Sources/ast-grep-mcp-swift/ast_grep_mcp_swift.swift

@@ -342,6 +342,8 @@ private func testMatchCodeRuleTool(_ args: [String: Value]?, configPath: String?
         throw MCPError.internalError("No matches found for the given code and rule. Try adding `stopBy: end` to inside/has rules.")
     }
 
+    // Note: Use plain text JSON here instead of jsonResourceContent to avoid
+    // "TypeError: Cannot read properties of undefined (reading 'uri')" in some MCP clients.
     let jsonText = try encodeJSON(matches)
     return .init(content: [.text(jsonText)], isError: false)
 }