[b-re-w]

Refs #45. This doesn't close it: the leak criterion is blocked by #98.

Test added

An embedded-runtime test in ksp-fixtures/app: compiled TypedPython code calls Kotlin through the binder.

• The buildTypedPythonBridge task builds a # typedpython: compiled module with pipeline.compile_module against the embedded CPython 3.14 headers. It uses the cpythonIncludeDirectories provider and reads EXT_SUFFIX from the extracted tree's sysconfigdata.
• The compiled code constructs a TpSample Kotlin proxy, calls its method, passes it back to Kotlin, passes a Python token to Kotlin, and loops with float math around the calls.

Results, all in the JVM:

• pass — the build/ABI premise: interpreter version, suffix and flavour match, and the compiled functions are C functions;
• pass — results identical to interpreted (float.hex), and Kotlin saw the same calls;
• pass — a Kotlin exception reaches the compiled caller as the same Python exception;
• skipped — the 10,000-call leak test, blocked by Binder: closing a PyObject argument inside an upcall crashes later (SIGSEGV in Py_XDECREF on the Cleaner thread) #98. When the cleaner releases the wrappers left by upcalls, the binder releases a reference twice and the JVM dies. The interpreted control crashes too. Re-enable it with -Dtypedpython.leakTest=true.

:ksp-fixtures:app:desktopTest: 74 tests, 0 failures, 1 skipped.

Defects found (filed, not fixed here: binder area)

• Binder: a KSP function returning a Kotlin class gives a generic _PmObject, not the rendered class proxy #94: a KSP function returning a Kotlin class gives an untyped _PmObject.
• Binder: closing a PyObject argument inside an upcall crashes later (SIGSEGV in Py_XDECREF on the Cleaner thread) #98: the binder double-releases on the cleaner path (memory safety).

The compile step needs a host Python with pyrefly 1.3.2, from -PtypedpythonPython or python-multiplatform-ksp/.venv. Without one the test reports itself as skipped. It runs on macOS only.