[TS PBT] Align property execution semantics

[CaelmBleidd]

Summary

This change gives concrete generation, examples, replay and shrinking one property execution contract, ready for downstream symbolic integration.

• Use one isolated input graph per attempt, preserving positional special values, aliases within an invocation, and the original counterexample before predicate mutation.
• Treat false preconditions as skips and discard-budget exhaustion as PRECONDITION_EXHAUSTED. Throwing and non-boolean preconditions are execution errors; even unreadable thrown values retain that classification.
• Treat false or throwing predicates as candidate violations, and non-boolean results as contract errors. Preserve the first contract error throughout shrinking.
• Use fast-check's total interruption budget for timeouts. User exceptions are classified independently of their message, so a predicate throwing Error('Property timeout: ...') remains a violation. Interrupted shrinking retains an already found counterexample.
• Keep Kotlin result invariants and primitive-only constant domains aligned with the adapter.

Scope

This PR contains the #384 execution contract and FastCheck behavior only. It is based on main, which already contains #350. PR #387 owns the dependent #351/#352 symbolic projection and search.

Validation

• ./gradlew :usvm-ts-pbt:check :usvm-ts-pbt:installDist :usvm-ts-pbt:detektMain :usvm-ts-pbt:detektTest: passed, 193 JVM tests, 59 adapter tests, no Detekt findings.
• New regressions reproduced the two exception-classification failures before their fixes and pass afterward, including sync/async paths and the Kotlin transport boundary.
• git diff --check: passed.
• CI run 35274293374: all six jobs passed. The unchanged JVM instrumentation dynamic timeout() test passed on one job rerun.

Closes #384