fix(api): sanitize status error bodies

[vincentkoc]

Summary

• sanitize HTTP and terminal handshake status error bodies before they reach CLI/Kong output
• tighten SSH gateway error rendering so attach failures strip full terminal escape sequences
• add regressions for API status errors, terminal handshake errors, and attach-path terminal errors

Validation

• clawpatch@latest review --limit 3 --model nova-alpha --reasoning-effort high: 0 findings
• autoreview --mode branch --base origin/main: clean, patch correct 0.84
• go test ./... && go vet ./...
• pnpm check
• pnpm test
• git diff --check