[plan] Simplify GenerateOutputSchema to use idiomatic For[T]() pattern

[github-actions]

Objective

Refactor GenerateOutputSchema function to use the more idiomatic For[T]() pattern instead of manual reflection.

Context

The current implementation uses reflect.TypeOf() indirection, but the library provides a cleaner generic For[T]() function.

Current Implementation

func GenerateOutputSchema[T any]() (*jsonschema.Schema, error) {
    var zero T
    typ := reflect.TypeOf(zero)
    return jsonschema.ForType(typ, &jsonschema.ForOptions{})
}

Proposed Implementation

func GenerateOutputSchema[T any]() (*jsonschema.Schema, error) {
    return jsonschema.For[T](nil)
}

Benefits

• Cleaner code (3 lines → 1 line)
• No reflect.TypeOf indirection
• More idiomatic library usage
• Better error messages with type names

Files to Modify

• pkg/cli/mcp_schema.go - Update GenerateOutputSchema function

Acceptance Criteria

• Function uses jsonschema.For[T](nil) pattern
• Existing tests still pass
• Code is more concise and readable
  Related to [plan] Upgrade and enhance google/jsonschema-go integration #6830

AI generated by Plan Command for discussion #6818