Summary

• register a memory capability runtime for memory-lancedb so core doctor/status surfaces can discover it as the active memory plugin
• expose the minimal runtime hooks doctor/status need: backend config resolution, search-manager status, embedding probe, and vector probe
• add regression coverage proving the plugin registers a visible runtime instead of only tools/hooks

Problem

memory-lancedb is a kind: "memory" plugin, but it did not register a memory runtime/capability. That meant the core memory-runtime path had nothing to resolve, so doctor/status could incorrectly report that no active memory plugin was registered even when the plugin was installed and working.

Validation

• pnpm vitest run extensions/memory-lancedb/index.test.ts
• pnpm lint extensions/memory-lancedb/index.ts extensions/memory-lancedb/index.test.ts
• pnpm build --filter memory-lancedb

Fixes openclaw#60177