fix: prevent silent passing on missing topology data + visible cleanup failures

predicates.ts (missing-fact discipline):
  - getTopologyValueBySubject: return -1 sentinel instead of ?? 0
    when topology data is missing/unset. NaN and negative values
    also treated as missing. Previously returned 0 which was
    indistinguishable from root subject ID.
  - clippedByPredicate: return 'indeterminate' when clippingRoot < 0
  - inStackingContextPredicate: return 'indeterminate' when sc < 0
    or refSC < 0 (both subject and reference). Previously treated
    missing data as false — a silent wrong answer.
  - attachedToScrollContainerPredicate: return 'indeterminate' when
    scrollContainer < 0
  - escapeClippingChainOfPredicate: return 'indeterminate' when
    clippingRoot < 0

extraction.ts (cleanup visibility):
  - Promote fast-geometry and CDP cleanup failures from console.debug
    (invisible during test execution) to console.warn. Contaminated
    pages are now diagnosable without debug-log inspection.

658 tests pass.

packages/imhotep-playwright/src/extraction.ts

@@ -747,7 +747,8 @@ export async function extractWorldFastGeometry(
         el.removeAttribute('data-imhotep-runtime-id')
       }
     }).catch((err) => {
-      console.debug('[imhotep-playwright] fast-geometry cleanup evaluate failed:', err instanceof Error ? err.message : err)
+      // eslint-disable-next-line no-console
+      console.warn('[imhotep-playwright] fast-geometry cleanup failed:', err instanceof Error ? err.message : err)
     })
   }
 }
@@ -933,7 +934,8 @@ export async function extractWorldCdp(
         el.removeAttribute('data-imhotep-runtime-id')
       }
     }).catch((err) => {
-      console.debug('[imhotep-playwright] CDP cleanup evaluate failed:', err instanceof Error ? err.message : err)
+      // eslint-disable-next-line no-console
+      console.warn('[imhotep-playwright] CDP cleanup failed:', err instanceof Error ? err.message : err)
     })
     await sessionManager.detach()
   }

packages/imhotep-solver/src/predicates.ts

@@ -195,7 +195,10 @@ function getSubjectIndex(world: GeometryWorld, subjectId: number): number {
 
 function getTopologyValueBySubject(world: GeometryWorld, subjectId: number, values: number[]): number {
   const idx = getSubjectIndex(world, subjectId);
-  return idx >= 0 ? values[idx] ?? 0 : 0;
+  if (idx < 0 || idx >= values.length) return -1;
+  const v = values[idx];
+  // NaN or negative values indicate unset topology; treat as missing.
+  return (v === undefined || Number.isNaN(v) || v < 0) ? -1 : v;
 }
 
 function getSubjectDomNodeId(world: GeometryWorld, subjectId: number): number {
@@ -782,6 +785,7 @@ export const clippedByPredicate: PredicateEvaluator = {
     }
     // Simplified: check if subject's clipping root is the reference
     const clipRoot = getTopologyValueBySubject(world, subjectId, world.topology.clippingRootOf);
+    if (clipRoot < 0) return makePredicateResult('indeterminate');
     const pass = clipRoot === referenceId;
     // Determine clip kind from the clipping table entry for the reference.
     // Encoding: 1=contain:paint, 2=overflow:hidden/scroll/auto
@@ -807,11 +811,13 @@ export const inStackingContextPredicate: PredicateEvaluator = {
       return makePredicateResult('indeterminate');
     }
     const sc = getTopologyValueBySubject(world, subjectId, world.topology.stackingContextOf);
+    if (sc < 0) return makePredicateResult('indeterminate');
     const subjectHasSC = sc > 0;
 
     if (tuple.length >= 2 && tuple[1] !== undefined && tuple[1] !== 0) {
       const referenceId = tuple[1];
       const refSC = getTopologyValueBySubject(world, referenceId, world.topology.stackingContextOf);
+      if (refSC < 0) return makePredicateResult('indeterminate');
       const pass = subjectHasSC && refSC > 0 && sc === refSC;
       return makePredicateResult(pass ? 'true' : 'false', { stackingContext: sc, referenceStackingContext: refSC }, [subjectId, referenceId]);
     }
@@ -829,6 +835,7 @@ export const attachedToScrollContainerPredicate: PredicateEvaluator = {
       return makePredicateResult('indeterminate');
     }
     const scrollContainer = getTopologyValueBySubject(world, subjectId, world.topology.scrollContainerOf);
+    if (scrollContainer < 0) return makePredicateResult('indeterminate');
     const pass = scrollContainer > 0 && scrollContainer === referenceId;
     return makePredicateResult(pass ? 'true' : 'false', { scrollContainer, referenceId }, [subjectId]);
   },
@@ -854,6 +861,7 @@ export const escapeClippingChainOfPredicate: PredicateEvaluator = {
     const overflowBottom = Math.max(0, sRect.bottom - clipRect.bottom);
     const overflow = overflowLeft + overflowTop + overflowRight + overflowBottom;
     const clippingRoot = getTopologyValueBySubject(world, subjectId, world.topology.clippingRootOf);
+    if (clippingRoot < 0) return makePredicateResult('indeterminate', { hasClippingRoot: 0 }, [subjectId, referenceId]);
     const clippedByReference = clippingRoot === referenceId;
     const pass = overflow > 0 && !clippedByReference && ancestry !== false;
     const metrics: Record<string, number> = {