v0.3.0: pinned launch commands, upgrades that reach installed agents

Upgrades now reach installed agents. Harness configs launch a pinned command, so an agent starts fast and works offline once that version is cached, and re-running setup moves the pin deliberately. Until now, npx kept the first version it cached for the unpinned command and never checked for a newer one, so installs made with 0.2.x never saw the 0.2.1 fixes.

If you already installed jev-code, run this once:

npx -y @french-castle/jev-code@latest setup

New install:

npx -y @french-castle/jev-code@latest setup
npx -y @french-castle/jev-code@latest doctor --live

Changed

• Harness configs now launch a pinned command, npx -y @french-castle/jev-code@<version> mcp.
  npx keeps the first version it cached for an unpinned name and never checks for a newer one,
  so earlier installs were frozen on whatever they first fetched; run
  npx -y @french-castle/jev-code@latest setup once to move to a pinned command. Re-running setup
  replaces an existing registration whose command differs, including through claude mcp and
  codex mcp, and reports it as updated.
• doctor shows the pinned version of each registration and says when to re-run setup.
• The README and guides invoke setup and doctor with @latest, for the same reason.
• npm version runs scripts/sync-version.mjs, which keeps the plugin manifest, the skill
  metadata, the plugin .mcp.json, and the documented launch commands on the new version.

Fixed

• Config backups taken within the same second no longer overwrite each other.
• The Codex config.toml editor keeps the file's line endings and handles an env sub-table
  declared before its parent.

Full details: CHANGELOG.md. Previous release: v0.2.1.