#21003: feat(memory): add durable memory_write + memory_upsert tools

## Summary - add new durable memory tools: `memory_write` (append) and `memory_upsert` (keyed update/insert) - wire new tools through runtime + memory-core extension + tool-policy groups - update prompt/tool metadata and docs for new memory tool capabilities - add/extend tests for memory tool behavior and policy handling - serialize same-process concurrent writes with a per-file in-process mutex ## Why This enables explicit, structured durable-memory writes when users ask the assistant to remember or update long-term context, while keeping tool-policy controls explicit. ## Validation - `pnpm vitest run --config vitest.e2e.config.ts src/agents/tools/memory-tool.e2e.test.ts src/agents/pi-tools.policy.e2e.test.ts` ## Follow-up split Cross-process file-lock hardening was split into a stacked follow-up PR (per review request): - https://github.com/SmithLabsLLC/openclaw/pull/1