v1.2.0

DevEx polish — CLI UX + README clarity. No new architecture
subsystems. No schema changes. No new MCP tools. Pure surface polish
across the developer-facing edges that were rough on first contact.

Changed

• Top-level kairo --help gains a 3-line Quick start callout
  above the command list so first-time users see action items
  (cd → init → doctor → status) instead of a flat command catalogue.
  The footer hint now points to kairo doctor when something looks
  off, not just kairo help <command>.

• kairo init now detects the MCP host on PATH (currently
  recognises Claude Code; structured to grow) and prints a concrete
  3-step Next steps block tailored to what was found:

  Initialised
    .mcp.json:   written
    .gitignore:  appended
    mcp host:    claude
  
  Next steps
    1. Open Claude Code in this project: claude
    2. Inside the session, run: /mcp
       → you should see  kairo · connected · 41 tools
    3. If anything looks off, run: kairo doctor
  

  The --json output gains a detectedHost field. Existing
  mcpJson / gitignore / projectRoot fields are unchanged.

• kairo doctor now correctly handles the case where it's run
  from inside the kairo-mcp dev repo itself (where dist/index.js
  lives at the repo root, not under node_modules/kairo-mcp/). The
  kairo-mcp installed and version match checks fall back to the
  self-install path when node_modules/kairo-mcp/ is absent but the
  current package.json says name: "kairo-mcp".

• README.md Quick start and Real workflow sections updated to
  the v1.2.0 output: realistic kairo init block with detected host

  • next-steps; install line no longer pins to a stale v1.1.0 tag.

Notes

• 193/193 tests still pass. CI matrix (6 cells + install-smoke) all
  green on v1.1.3 baseline; v1.2.0 changes don't touch any tested
  invariant.
• Stability registry unchanged. No new MCP tools. No new persisted
  artefacts. The CLI surface remains experimental per ADR-0016.
• Success condition for this slice (per the brief): "a new
  developer should understand Kairo and run it on a repo in under
  5 minutes." The init → doctor → status happy path now takes
  3 commands and reads honestly at every step.