Add Gemini CLI appendix to primitives matrix

[cobusgreyling]

Goal

Map loop primitives to Gemini CLI (gemini command) for users who run agentic loops from the terminal.

Files

• docs/primitives-matrix.md
• examples/README.md (tool directory row)

Acceptance criteria

• New ## Appendix: Gemini CLI section
• Cover scheduling (cron/systemd), skills/context files, state, maker/checker via separate sessions
• Week-one Daily Triage example — read STATE.md, update triage sections only, no source edits
• Link to official Gemini CLI docs where primitives are named differently

Estimated time: ~30 minutes

Comment "I'll take this" to get assigned.