Harden operation state-writer parity

[screenleon]

What changed

• declare operation create/update strategies and the append-locked children.jsonl relation in core/state/layout.yaml
• make the layout's writer entry-point inventory exactly match every public mutating API in state-writer.sh
• extend the production state-write boundary ratchet to operation projections, child relations, relative paths, and split-line writes
• add operation collision/upsert/append parity coverage, including the mkdir-lock fallback
• make the affected-test planner select state-store, layout-parity, and operation tests for state-writer changes

Why

The CC-508 parent-operation control plane introduced durable operation projections and child relations, but those writes were not fully represented by the declarative state layout or the production write-boundary parity tests. That left future drift or direct-write bypasses less visible than the equivalent task/run state paths.

Impact

This is a contract, test, and affected-test-planner hardening change. It does not alter production runtime behavior.

Validation

• PR gate: GO (critic and architecture approved; QA passed)
• authoritative full suite: 97 passed, 0 failed, 0 skipped
• test-state-layout-parity: 7/7
• test-layer-boundaries: 31/31
• test-run-tests: 23/23
• test-pmctl-operation: 13/13
• test-state-store: 80/80
• ShellCheck: 231 files
• git diff --check: clean