[TS PBT] Align property execution semantics

[CaelmBleidd]

Summary

• define one normative property execution contract for concrete runs, replay, shrinking, and downstream symbolic integration
• run each FastCheck attempt on an isolated input graph while preserving aliases within that invocation
• classify false preconditions as skips, exhaustion as PRECONDITION_EXHAUSTED, and throwing or non-boolean preconditions as execution errors
• keep predicate false and escaping exceptions as violations while rejecting non-boolean predicate results as contract errors
• preserve positional special values and pre-mutation counterexamples through shrinking and replay
• add concrete contract fixtures and regression coverage without introducing a second execution path

Scope

This PR contains the #384 execution contract and FastCheck behavior only. USVM domain projection and violation search are intentionally kept out; #387 implements #351 and #352 on top of this PR.

Validation

• npm test in fast-check-adapter: 55 passed
• ./gradlew :usvm-ts-pbt:check :usvm-ts-pbt:installDist: 192 JVM tests and 55 packaged adapter tests passed
• git diff --check: passed
• CI run 34232390596: all jobs passed

Closes #384