feat(rules): add repository bootstrap and rule catalog

[rgdevme]

Summary

• add rules.dir configuration with root-relative fallback for existing configurations
• add agnos rules bootstrap [source] with interactive and -y selection
• discover Markdown rules recursively from repository or local sources
• preserve catalog-relative paths and overwrite selected destination files deterministically
• support dry runs, provider selection, initialization defaults, and clear early warnings
• add a reusable catalog of general and technology-specific rule fragments
• document the bootstrap workflow and configuration behavior

Validation

• changed-file Prettier check passes
• pnpm lint passes with 108 existing warnings and no errors
• pnpm typecheck passes
• pnpm test passes: 40 files and 307 tests
• pnpm build passes

Notes

The repository-wide Prettier check still reports existing formatting issues outside the files changed by this branch.