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.ts

@@ -97,7 +97,7 @@ export interface FormulaResult {
 // ---------------------------------------------------------------------------
 
 export interface DomainResolver {
-  resolve(domain: DomainRef): DomainValue | undefined;
+  resolve(domain: DomainRef, env?: BindingEnv): DomainValue | undefined;
 }
 
 // ---------------------------------------------------------------------------
@@ -262,7 +262,7 @@ function evaluateForAll(
   // Resolve domains and build join specs.
   const specs: JoinSpec[] = [];
   for (const binding of formula.bindings) {
-    const domain = state.resolver.resolve(binding.domain);
+    const domain = state.resolver.resolve(binding.domain, env);
     if (!domain) {
       addDiagnostic(
         state,
@@ -403,7 +403,7 @@ function evaluateExists(
   // Resolve domains and build join specs.
   const specs: JoinSpec[] = [];
   for (const binding of formula.bindings) {
-    const domain = state.resolver.resolve(binding.domain);
+    const domain = state.resolver.resolve(binding.domain, env);
     if (!domain) {
       addDiagnostic(
         state,