fix: out-of-box experience

[abienkowski]

Graceful startup without crash — the binary now works with zero config.

Changes:

• Missing config dir (3 languages): warn + empty policy set instead of crash
• Unwritable audit log (Go + Rust): warn + no-op logger instead of crash
• No Docker socket: proxy error (non-fatal), binary stays alive
• TS already handled both cases silently — no change needed