feat: serve version-matched skill instructions from the CLI

[suraciii]

Summary

• Add pages skill, a read-only command that prints a complete SKILL.md embedded in the installed binary.
• Replace the distributed Pages skill with a small bootstrap that uses the installed CLI or installs the current CLI with go install.
• Keep the three existing product actions unchanged. skill is CLI metadata and does not read configuration, inspect the filesystem, or access the network.

Distribution model

The repository skill is a stable entry point. It first tries:

pages skill

When the CLI is absent or too old, it installs the current version:

go install github.com/suraciii/pages@latest

It then runs pages skill again and follows the version-matched instructions. The bootstrap does not manage the user's shell, contain operational command syntax, or depend on Agent-specific install paths.

Command contract

• pages skill writes only the complete skill to stdout and exits 0.
• pages skill --help and pages skill -h write only Usage: pages skill to stdout and exit 0.
• Other arguments write an error and usage to stderr and exit 2.
• The emitted skill is embedded at build time and matches the CLI version.

Verification

• make ci
• go test -race ./...
• Linux, macOS, and Windows builds
• Standard skill validation for the bootstrap and embedded skills
• Built-binary output validation: pages skill matches the embedded SKILL.md byte-for-byte