CI: Run the TypedPython app fixture and fail when its tests skip

[b-re-w]

Leader decision on #119's follow-up.

• typedpython.yml: new app-fixture job (macos-latest). It creates a venv with pyrefly 1.3.2, runs :ksp-fixtures:app:desktopTest --rerun -PtypedpythonPython=<venv> after deleting old results, then fails if TypedPythonKotlinCallTest has no results or any skipped test. The workflow now also triggers on ksp-fixtures/app/**.
• ksp-fixtures/app/build.gradle.kts: when the bridge is not built, desktopTest logs one line, TypedPython bridge tests will be SKIPPED: <reason>. A local skip stays allowed. The test JVM gets PYTHONDONTWRITEBYTECODE=1, so no __pycache__ is left in src/desktopTest/typedpython.
• Includes Test: Always run the TypedPython leak test now that #98 is fixed #119's branch (the leak test no longer skips); merge Test: Always run the TypedPython leak test now that #98 is fixed #119 first.

Local verification (macOS arm64, JDK 21; the check step was run as written in the workflow):

• no venv: Gradle exit 0, warning line printed, check fails: 4 tests, 4 skipped.
• venv, before merging Test: Always run the TypedPython leak test now that #98 is fixed #119: check fails: 1 skipped (the leak test's old gate). The check catches a single skip.
• venv, with Test: Always run the TypedPython leak test now that #98 is fixed #119: Gradle exit 0, check passes: 4 tests, 0 skipped. No __pycache__ created; git status clean.