Sync codex-desktop-linux with v0.2.4 release content

[github-actions]

v0.2.4 released. Update codex-desktop-linux to pin/ship this version and mirror the relevant changes.

v0.2.4 changelog

Primarily a documentation release that refreshes the crates.io and npm README
pages; also bumps the MCP server's advertised version string to match.

Added

• Documented the screenshot MCP tool and the doctor capability map, which
  were missing from the README tool list and the MCP safety-contract table.
• A new "Environment variables" section covering runtime overrides
  (CU_DISABLE_ABS_POINTER, the COMPUTER_USE_LINUX_FORCE_PORTAL /
  FORCE_YDOTOOL pointer and keyboard knobs) and the npm wrapper install knobs
  (COMPUTER_USE_LINUX_BIN, DOWNLOAD_BASE, SKIP_DOWNLOAD, LOCAL_*).

Changed

• Stopped pinning explicit versions throughout the docs (README, npm README,
  Hermes skill). Install commands are now bare and download links use GitHub's
  /releases/latest redirect, so the docs no longer drift on every release.
• Dropped the version field from the Hermes skill frontmatter (optional per
  the agentskills.io standard) so it no longer mirrors the tool version.
• Friendlier README opening: warmer tagline and a verb-driven summary, with no
  sections removed.

Fixed

• install.sh now reads the current doctor readiness schema
  (.readiness.blockers, empty array means ready) instead of the removed
  .ready / .checks fields, so a fully provisioned system reports ready
  instead of always failing the doctor step. Restored the install.sh
  executable bit. (fix: update install.sh doctor readiness parsing to use current blockers schema #9)

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Opened automatically by the release workflow.