copilot-instructions.md references stale commands

[digitarald]

Problem

.github/copilot-instructions.md is out of date after the command consolidation in PR #17:

• References generate instructions and generate agents in the commands table — these were consolidated into the instructions command
• Missing --format flag (for choosing copilot-instructions.md vs AGENTS.md)
• Missing policy.ts service in the architecture table
• Missing pillar groups (Repo Health / AI Setup) context
• The generate command table still shows instructions|agents|mcp|vscode as the argument

When AI reads these instructions, it suggests outdated CLI invocations.

Suggestion

Run primer instructions to regenerate, or manually update the instructions to reflect the current CLI surface. Key corrections:

• generate accepts mcp|vscode only
• instructions is the standalone command with --format, --areas, --area, --output flags
• Add policy.ts to services table
• Mention pillar groups in readiness description