refactor: remove global registry fallbacks — factory pattern for test isolation

predicates.ts: Add populateDefaultPredicates(registry) accepting any
  PredicateRegistry. Add createDefaultPredicateRegistry() factory.
  registerDefaultPredicates() now delegates to populateDefaultPredicates
  on the global (backward compatible).

logic-engine.ts: Replace globalPredicateRegistry fallback with
  createDefaultPredicateRegistry() factory. Each evaluateLogic() call
  creates a fresh self-populated registry unless one is explicitly
  injected. No shared mutable state between evaluations.

engine.ts: Same pattern for clauses — add populateDefaultClauses(registry),
  createDefaultClauseRegistry() factory. registerDefaultClauses() now
  delegates to populateDefaultClauses on the global. evaluate() replaces
  globalClauseRegistry fallback with createDefaultClauseRegistry().

registry.ts: @deprecated tag on registerClause with migration note.

Both global registries remain for backward compatibility via the
  deprecated registerDefault*() functions, but the evaluation engines
  no longer depend on them. Every evaluation gets its own registry by
  default, so custom predicates registered by one test cannot leak
  into another. Tests using explicit registry injection are unaffected.

662 tests pass (315 DSL + 141 core + 149 solver + 57 E2E).

packages/imhotep-solver/src/predicates.ts

@@ -1200,45 +1200,56 @@ export const hasGapPredicate: PredicateEvaluator = {
 /** Sentinel registered to detect if defaults were already installed. */
 const DEFAULT_SENTINEL = '__imhotep_defaults_registered__'
 
-export function registerDefaultPredicates(): void {
-  if (globalPredicateRegistry.get(DEFAULT_SENTINEL)) return
-  // Register sentinel first so partial failures don't cause infinite loops.
-  globalPredicateRegistry.register({
+/** Populate a PredicateRegistry with all 33 built-in predicates (idempotent). */
+export function populateDefaultPredicates(registry: PredicateRegistry): void {
+  if (registry.get(DEFAULT_SENTINEL)) return
+  registry.register({
     descriptor: { name: DEFAULT_SENTINEL, arity: 0, domains: [], requiredFacts: [] },
     evaluateTuple: () => ({ truth: 'indeterminate' }),
   })
-  registerPredicate(widthPredicate);
-  registerPredicate(heightPredicate);
-  registerPredicate(abovePredicate);
-  registerPredicate(belowPredicate);
-  registerPredicate(leftOfPredicate);
-  registerPredicate(rightOfPredicate);
-  registerPredicate(insidePredicate);
-  registerPredicate(containsPredicate);
-  registerPredicate(overlapsPredicate);
-  registerPredicate(alignedWithPredicate);
-  registerPredicate(centeredWithinPredicate);
-  registerPredicate(atLeastPredicate);
-  registerPredicate(atMostPredicate);
-  registerPredicate(betweenPredicate);
-  registerPredicate(clippedByPredicate);
-  registerPredicate(attachedToScrollContainerPredicate);
-  registerPredicate(escapeClippingChainOfPredicate);
-  registerPredicate(aspectRatioPredicate);
-  registerPredicate(inStackingContextPredicate);
-  registerPredicate(separatedFromPredicate);
-  registerPredicate(leftAlignedWithPredicate);
-  registerPredicate(rightAlignedWithPredicate);
-  registerPredicate(topAlignedWithPredicate);
-  registerPredicate(bottomAlignedWithPredicate);
-  registerPredicate(intersectsPredicate);
-  registerPredicate(touchesPredicate);
-  registerPredicate(hasGapPredicate);
-  registerPredicate(besidePredicate);
-  registerPredicate(nextToPredicate);
-  registerPredicate(adjacentPredicate);
-  registerPredicate(touchingPredicate);
-  registerPredicate(nearPredicate);
-  registerPredicate(underPredicate);
-  registerPredicate(withinPredicate);
+  registry.register(widthPredicate)
+  registry.register(heightPredicate)
+  registry.register(abovePredicate)
+  registry.register(belowPredicate)
+  registry.register(leftOfPredicate)
+  registry.register(rightOfPredicate)
+  registry.register(insidePredicate)
+  registry.register(containsPredicate)
+  registry.register(overlapsPredicate)
+  registry.register(alignedWithPredicate)
+  registry.register(centeredWithinPredicate)
+  registry.register(atLeastPredicate)
+  registry.register(atMostPredicate)
+  registry.register(betweenPredicate)
+  registry.register(clippedByPredicate)
+  registry.register(attachedToScrollContainerPredicate)
+  registry.register(escapeClippingChainOfPredicate)
+  registry.register(aspectRatioPredicate)
+  registry.register(inStackingContextPredicate)
+  registry.register(separatedFromPredicate)
+  registry.register(leftAlignedWithPredicate)
+  registry.register(rightAlignedWithPredicate)
+  registry.register(topAlignedWithPredicate)
+  registry.register(bottomAlignedWithPredicate)
+  registry.register(intersectsPredicate)
+  registry.register(touchesPredicate)
+  registry.register(hasGapPredicate)
+  registry.register(besidePredicate)
+  registry.register(nextToPredicate)
+  registry.register(adjacentPredicate)
+  registry.register(touchingPredicate)
+  registry.register(nearPredicate)
+  registry.register(underPredicate)
+  registry.register(withinPredicate)
+}
+
+/** Create a fresh PredicateRegistry with all 33 built-in predicates pre-registered. */
+export function createDefaultPredicateRegistry(): PredicateRegistry {
+  const registry = new PredicateRegistry()
+  populateDefaultPredicates(registry)
+  return registry
+}
+
+export function registerDefaultPredicates(): void {
+  populateDefaultPredicates(globalPredicateRegistry)
 }