feat: implement variable-bound FOL domain resolution for descendants/children

- Extend DomainResolver.resolve() signature to accept optional BindingEnv
  so that parentVar domains can be resolved with runtime variable bindings
- Pass BindingEnv through evaluateForAll/evaluateExists to resolver calls
- Add buildAncestorIndex() to precompute DOM ancestor sets from CDP data
- SelectorDomainResolver now filters descendant domains by the bound parent
  when domain.parentVar is present and ancestor index is available
- Return undefined for parentVar domains when no ancestor index or env
  (prevents silent fallback to global domain resolution)
- Update all test DomainResolver mocks for new resolve interface
- Add 10 unit tests covering ancestor index construction, backward compat,
  descendant filtering, exclusion of non-descendants, empty descendants,
  missing parentVar/env, and no-ancestor-index safety

packages/imhotep-solver/src/logic-engine.test.ts

@@ -160,7 +160,7 @@ function makeWorld(overrides?: Partial<GeometryWorld>): GeometryWorld {
 
 function makeResolver(domains: Map<string, DomainValue>): DomainResolver {
   return {
-    resolve(domain: DomainRef): DomainValue | undefined {
+    resolve(domain: DomainRef, _env?): DomainValue | undefined {
       const key = domain.selector ?? domain.domain;
       return domains.get(key);
     },