Draft: add core agent-plane schema scaffolds

[mdheller]

What this lands

This draft PR adds the first six core agent-plane schema scaffolds:

• ExecutionDecision.json
• AgentSession.json
• ExecutionSurface.json
• SkillManifest.json
• MemoryEntry.json
• SessionReceipt.json

Why now

The current public sourceos-spec surface is strong on metadata / governance / batch-run objects, but it does not yet name the core runtime law needed by the agent plane. These scaffolds are the smallest clean-room patch that starts to close that gap without overloading existing data-plane objects such as CapabilityToken, PolicyDecision, WorkloadSpec, or RunRecord.

Non-goals in this PR

This draft does not yet:

• patch openapi.yaml
• patch asyncapi.yaml
• add tool/session/promotion/reversal artifacts
• add the second-wave leak-derived objects (SessionReview, ExperimentFlag, RolloutPolicy, TelemetryEvent, FrustrationSignal, ReleaseReceipt)

Follow-up queue

1. Wire the new schema family into OpenAPI / AsyncAPI.
2. Patch SociOS-Linux/agentos-starter interfaces (MemoryAPI, Orchestrator, Executor).
3. Extend SocioProphet/agentplane bundle / artifact schemas.
4. Add validator/admission wiring in SociOS-Linux/imagelab.
5. Normalize SourceOS-Linux/openclaw runtime surfaces against these contracts.

Clean-room posture

This work is based on public repo surfaces and public reporting about Claude Code’s leak-era lessons. It does not copy proprietary Anthropic implementation details.