Types that appeared only in TypeScript interface members — property
signatures like `value?: Partial<IPage>` and method signatures like
`fetchPage(arg: IPage): IOrderField` — were not being captured at
extraction time, so the resolver never built `references` edges for
them. `codegraph_impact`/`codegraph_callers` on the named type missed
every consumer that imported it solely to use it in an interface shape.
Add a `property_signature` / `method_signature` branch in `visitNode`:
when inside a class-like node (which covers interfaces) and the
language supports type annotations, call `extractTypeAnnotations` with
the parent (interface) node ID as the edge source. No property/method
node is created — only unresolved references that the resolver wires
the same way it wires field and parameter type references elsewhere.
