release: v5.0.0 — conservative subagent support (parent seed + child recovery)

- Add workspace resolution helpers (isSubagentSession, parseParentAgentId, resolveAgentWorkspace)
- Parent→Child seeding: inject parent CURRENT_STATE.md into subagent context at startup
- Child→Parent recovery: new subagent_ended hook reads child unsurfaced results, merges into parent
- Add subagentSeed and subagentRecovery config keys (both default: true)
- Add /mc subagents command for cross-workspace state overview
- Bump lifecycle plugin to v5.0.0, mc-plugin to v2.1.0

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "memory-continuity",
-  "version": "4.0.0",
+  "version": "5.0.0",
   "description": "Zero-dependency memory continuity for OpenClaw — plain markdown, lifecycle hooks, no vector DB.",
   "main": "index.js",
   "type": "module",