feat(mcp): add stale install and API compatibility checks to doctor

[JSONbored]

Problem

A stale global install can make new commands appear missing. For example, a user may have gittensory-mcp@0.1.x installed globally while npm latest supports the agent commands.

Desired behavior

gittensory-mcp doctor and gittensory-mcp status should detect stale local package versions and API compatibility mismatches, then print exact upgrade guidance.

Implementation notes

• Start in the MCP package CLI command handlers.
• Compare local package version against npm latest when network is available.
• Check API compatibility/version endpoint if available.
• Fail gracefully when npm or API checks are unavailable.
• Avoid printing auth tokens, local absolute paths, or environment dumps.

Public/private boundaries

This is local CLI output only. Do not add backend public output or GitHub comments.

Acceptance criteria

• Stale global install is reported clearly.
• Output includes an exact upgrade command such as npm install -g @jsonbored/gittensory-mcp@latest.
• npx @jsonbored/gittensory-mcp@latest ... is suggested as a no-install fallback.
• Network failure produces a warning, not a hard failure.
• No tokens or sensitive local data are printed.

Tests

• Latest version available.
• Local version stale.
• Local version current.
• npm registry unavailable.
• API compatibility unavailable.
• Output redaction regression.