Feature: install, update, and doctor improvements for npx beta #94

Research-backed TODO

The CLI package is alpha-ready but npm publishing is blocked by auth. Before beta, the install path should include stronger smoke tests, update checks, and platform-specific troubleshooting.

Acceptance criteria

• Expand codex-claw doctor to validate Codex CLI, Node, pnpm/npm, git, state directory, and port availability.
• Add an install smoke test script that runs from the packed tarball and from npm once published.
• Document Windows, macOS, and Linux install/update paths.
• Add clear messages for npm auth, package not found, locked ports, and missing Codex CLI.

Public research basis

• OpenAI Codex CLI README documents shell, PowerShell, npm, Homebrew, and release-binary install paths.
• Open WebUI emphasizes effortless setup as a key feature.
• Aider and Continue both provide package-manager CLI installation paths.

Non-goals

• No claiming stable latest until beta criteria are met.
• No installer that writes outside the requested directory without confirmation.

Source set

• OpenAI Codex CLI - local terminal coding agent, installer paths, IDE/desktop context.
• OpenHands - local GUI with REST API + SPA, CLI, cloud collaboration/integrations.
• Aider - repo maps, git integration, image/web context, lint/test loops.
• Continue - source-controlled AI checks as markdown agents in CI.
• Open SWE - isolated sandboxes, AGENTS.md context, curated tools, subagents, Slack/Linear handoff.
• Model Context Protocol servers - tool/server registry pattern, filesystem/git/memory/fetch examples, security warnings.
• Open WebUI - responsive/PWA UI, RAG/web browsing, artifact storage, permissions.
• OpenCode - coding-agent modes, plan/build separation, subagent pattern.
• Cline - autonomous coding agent as SDK, IDE extension, and CLI assistant.
• Roo Code - agent-oriented coding workflow inside the editor.