feat: qualify durable fenced client operations

[jstar0]

Summary

• add the leased_v1 long-running client operation protocol on the existing conversation turn
• enforce PostgreSQL-authoritative attempt fencing, lease reclaim, bounded checkpoints, terminal idempotency, and semantic side-effect boundaries
• integrate the maintained OpenClaw plugin hooks with fenced tool results and progress checkpoints
• retain Hermes on the bounded compatibility path
• add the frozen W36 case, exact macOS acceptance runner, evidence, and design/spec documentation

Verification

• exact revision runtime run: bc0eb0e
• W36 hard gates: 28/28
• OpenClaw: 76/76, typecheck, build, pack dry-run
• native PostgreSQL dump/restore and restored bearer-token authentication: pass
• no credentials persisted; temporary cluster removed

The W36 run uses a deterministic mock provider because it qualifies durability, fencing, restart, isolation, and semantic side-effect contracts rather than model quality.