fix(cli): use MCP logging levels

[Bortlesboat]

Summary

Align the CLI's --log-level validation with the MCP logging specification. The accepted values now come from the SDK's LoggingLevelSchema, so the CLI no longer rejects valid RFC 5424 levels or forwards the non-spec trace and warn aliases.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Documentation update
• Refactoring (no functional changes)
• Test updates
• Build/CI improvements

Changes Made

• Derive CLI logging levels from the MCP SDK schema instead of a parallel hardcoded list.
• Pass the schema-derived level to Client.setLoggingLevel without an unsafe cast.
• Pin schema parity and reject trace/warn at the CLI validation boundary.

Related Issues

Fixes #1734

Testing

• Tested in UI mode
• Tested in CLI mode
• Tested with STDIO transport
• Tested with SSE transport
• Tested with Streamable HTTP transport
• Added/updated automated tests
• Manual testing performed

Test Results and/or Instructions

• Full production build: npm run build
• CLI TypeScript build: npm run build-cli
• Focused regression: 3 passed (MCP spec logging levels and both non-spec aliases)
• Prettier check and git diff --check passed for both changed files

The broad CLI suite produced 60 passes and 28 Windows-only failures after successful HTTP responses because Node 24 aborted during transport teardown with UV_HANDLE_CLOSING. The affected focused tests do not use that teardown path and pass consistently.

Checklist

• Code follows the style guidelines (formatted and checked with Prettier)
• Self-review completed
• Code is commented where necessary
• Documentation updated (README, comments, etc.)

Breaking Changes

None.

Additional Context

Documentation is unchanged because the help text does not enumerate logging levels; its validation error now renders the SDK-derived list automatically. The change is limited to two CLI files.