feat(pm): graph adoption & reconcile contract [PM-A]

[rickylabs]

Part of #510.

The full adoption contract the POC lacked (its "singleton" was a port probe; a partial stack read as running): durable process identity, PID/command validation, stale-registry behavior, ownership/restart authority, teardown semantics for adopted members.

• Archetype 2 pm-core + Archetype 3 runtime gates. Depends on PM-3 [process-manager PM-3] Core package scaffold: ports + KV registry adapter #514.
• gate: adoption state machine under fake clock; failure/cancellation cases
• gate: contract types public in contracts/v1 — jsr rubric

Design source: PR #822 (rfc.md + plan.md rev 10, 9-cycle adversarial trail) in .llm/runs/rfc-single-deployment--orchestrator/. (plan.md §A.2)