fix: cleanup dead code and improve error display

[mikolajbadyl]

• Removed dead ExecuteTest handler from executeTool() and handleToolResult() — agent only uses ExecuteTestGroup
• Inlined deprecated showToolWidget() wrapper into call sites
• Removed stale ExecuteTest case from conversation restore display names
• Fixed headless exit code: connection errors (e.g. connection refused) now correctly set exit code 1 instead of reporting success
• Added friendlyError() helper — HTTP errors display as connection refused instead of full Go error chain

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Overview

The PR performs cleanup and refactoring:

• Removes deprecated/internal ToolExecuteTest handling (now dispatched internally via ExecuteTestGroup)
• Replaces deprecated showToolWidget() with proper showToolMessage() + updateViewport() pattern
• Adds friendlyError() function for human-readable error messages
• Sets headlessExitCode = 1 on test failures in headless mode

All changes appear intentional and correct. The ToolExecuteTest tool is marked as "internal" in tools.go:12 and is never exposed to the LLM, so removing its direct handlers is safe.

Files Reviewed (4 files)

• internal/cli/handlers.go - Removed ToolExecuteTest handling (internal tool)
• internal/cli/update.go - Replaced deprecated showToolWidget calls
• internal/cli/update_tests.go - Added friendlyError and headless exit code handling
• internal/cli/utils.go - Added friendlyError function