feat(skill): expose discovery compatibility details

[yunze7373]

Summary

• expose public discovery serviceVersion, mcpUrl, and bounded supportedClients in standalone doctor --json
• document the compatibility diagnostics and bump only the standalone Skill patch to 1.1.9
• preserve anonymous, credential, health-check, degraded-discovery, API, and scope behavior

Source evidence and user value

MemoryOS discovery 0.4.346 advertises these compatibility fields, and the top-level CLI doctor reports them. The standalone Skill already reads the same public document but omitted them, forcing agents to parse raw discovery output.

Validation

• verify-candidate.mjs: passed; 4 allowlisted files, 24 added lines, 1.1.8 -> 1.1.9
• npm run lint: passed
• focused tests: 31/31 passed
• npm run pack:dry-run: passed

Risk boundary

No npm version or publication, service/API/auth/credential/scope/deletion/privacy/retention/dependency/license change, skill-card.md, workflow, release script, allowlist, or direct main push. ClawHub baseline is xmemo@1.1.8, moderation clean, with matching source hashes.