[TS PBT][P0] Align and simplify property execution semantics

[CaelmBleidd]

Summary

• define one normative execution contract for concrete runs, replay, shrinking, projection, and symbolic search
• run precondition and predicate over one isolated invocation graph while preserving aliases and mutation isolation
• classify throwing and non-boolean preconditions as execution errors, and distinguish discard exhaustion from property violations
• align Node constant-domain validation with the Kotlin model
• add shared TypeScript fixtures and observable Node/JVM contract regressions

Validation

• npm test: 55 tests passed
• ./gradlew :usvm-ts-pbt:test :usvm-ts-pbt:detekt --rerun-tasks: 192 tests passed, 0 Detekt findings
• ./gradlew :usvm-ts-pbt:check :usvm-ts-pbt:installDist: successful
• git diff --check: successful
• installed adapter contains the new diagnostics, structuredClone invocation boundary, and precondition-exhausted result kind

Closes #384