feat: hierarchical dispatch model for meta orchestrator

[m2ux]

Summary

• Implements a persistent master orchestrator model where the meta workflow dispatches client workflows to independent sub-agents instead of abandoning the meta session
• Adds dispatch_workflow and get_workflow_status MCP tools for creating independent client sessions with parent-child correlation
• Replaces the old meta activity flow (start-workflow → resume-workflow) with dispatch-workflow that manages client lifecycle inline (dispatch → await result → handle checkpoints → evaluate transitions)
• Sessions are never shared — meta agent holds the meta token, client agents hold their own client tokens

Key Changes

Server code:

• SessionPayload.psid — optional parent SID field for trace correlation
• dispatch_workflow tool — creates client session, generates dispatch package (token, prompt, metadata)
• get_workflow_status tool — polls client session status without requiring its token

Workflow data:

• New 02-dispatch-workflow.toon activity with 7-step inline dispatch lifecycle
• Updated 10-orchestrator-management.toon with dispatch-client, handle-client-checkpoint, process-client-result phases
• Updated 11-worker-management.toon for independent client agents with checkpoint yield protocol
• Updated 05-worker-prompt-template.md for client agents using their own session tokens
• New 09-client-dispatch-protocol.md documenting the dispatch → manage → complete lifecycle
• Updated 03-end-workflow.toon to verify all dispatched clients completed

Tests:

• 13 new tests covering psid propagation, dispatch session creation, status extraction, parent-child correlation, and recursive dispatch

Test plan

• npm run typecheck passes
• npm test passes (28 tests total, 13 new)
• Manual test: start a meta session, dispatch a client workflow, verify checkpoint yield chain works end-to-end
• Verify client session independence — no token cross-contamination
• Verify trace correlation: parent SID appears in client session payload