pre-flight-checks

Diagnostic skill for the SfIntelligence vault. Use when the user invokes /sfi-status, says "is something wrong?", "the vault feels off", "something looks stale", "are we connected?", "is the index current?", or when a previous sfi.* MCP call returned a degraded or unhealthy status, an unexpected error envelope, or two consecutive errors. Runs three probes — sfi.health_check, sfi.get_manifest, and sf org list --json…