feat(memory): add agent safe APIs

docs/memory-graph-runtime.md

@@ -33,6 +33,13 @@ with `markitect-tool`.
 - `MemoryRuntimeService.compact_memory()` creates a deterministic summary node,
   preserves source spans/provenance, optionally retires source nodes, and appends
   a compaction event.
+- `MemoryRuntimeService.plan_memory_update()` creates dry-run update plans with
+  source and policy explanations.
+- `MemoryRuntimeService.apply_memory_update()` requires explicit approval for
+  durable writes when a plan is review-gated.
+- `MemoryRuntimeService.export_context_package_inputs()` emits
+  Markitect-compatible context package input envelopes without invoking the
+  Markitect compiler.
 
 ## Boundary
 
@@ -48,6 +55,7 @@ with `markitect-tool`.
 - append-only event storage
 - permission-aware retrieval and context assembly
 - retention, refresh, compaction, review gates, and audit behavior
+- agent-safe update plans and Markitect-compatible export envelopes
 
 `infospace-bench` should consume these records and Markitect fixtures to measure
 retrieval quality, latency, budget pressure, and regression behavior.