架构优化

docs/CORE_GUIDE.md

@@ -100,8 +100,11 @@ static_assert(Property::writable);
 static_assert(Property::runtime_copy_writable);
 using Value = Property::value_type;
 using Accessor = Property::accessor_type;
+using Dependencies = Property::dependency_spec;
 ```
 
+Every custom `Property_Accessor` must declare `using dependency_spec = ...`. Use `No_Property_Dependencies` when it has no dependencies; there is no implicit fallback.
+
 A `read_only` field reports:
 
 ```cpp
@@ -513,7 +516,7 @@ computed_property<Device, int>(depends_on<&Device::min_speed, &Device::max_speed
 }, key<"speed_span">)
 ```
 
-`depends_on<...>` makes dependencies explicit Schema facts. `depends_on_keys<"a", "b">` is available when key-based declaration is more appropriate. A computed view can read only its declared direct dependencies.
+`depends_on<...>` makes dependencies explicit Schema facts. `depends_on_keys<"a", "b">` is available when key-based declaration is more appropriate. `depends_on<>` is a valid explicit zero-dependency declaration. A computed view can read only its declared direct dependencies.
 
 Writable dependencies that must form one snapshot should share a synchronization domain with each other:
 
@@ -526,7 +529,9 @@ synchronization(
 
 Do not put the computed property itself in a synchronization rule. Its read slot is derived from the dependency graph; a schema or per-instance topology is rejected when synchronized dependencies do not resolve to one domain. Read-only stored dependencies need no lock slot.
 
-`schema_property_dependency_indices<Schema, Index>()` exposes the direct dependency indices for schema consumers.
+`schema_property_dependency_indices<Schema, Index>()` exposes the direct dependency indices for schema consumers. `schema_dependency_graph_acyclic<Schema>()` exposes the DAG invariant; `object_schema(...)` rejects cyclic dependency graphs at compile time.
+
+A descriptor stores Attributes and Constraints in one metadata tuple. `for_each_metadata()` traverses both kinds, `for_each_attribute()` traverses only Attributes, and `for_each_constraint()` traverses only Constraints.
 
 ## 21. Trusted accessor properties