ci(android): print full assertion messages for failing tests

CI run 3161 reported seven failures as bare "java.lang.AssertionError at
UpdateVeilControllerTest.kt:87" — and line 87 is the test's own `fun ... =
runTest {` line, not the assertion. Gradle picks the first stack frame
belonging to the test class, and assertions inside a `runTest { }` lambda
live in a generated suspend-lambda class that gets filtered out, so every
failure in a coroutine test collapses to the function declaration. With the
HTML report unreachable from CI, that leaves nothing to debug from.

testLogging with exceptionFormat = FULL prints the assertion message and the
whole stack trace for failures, which is what makes a coroutine-test failure
diagnosable at all here.

Also drop the NonCancellable floor-join from UpdateVeilController's finally.
Honouring the minimum hold while the scope is being torn down is pointless —
nothing is left to render the veil — and a finally that suspends is a finally
that can resist cancellation. The floor is now awaited in the try instead.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

android/app/build.gradle.kts

@@ -210,4 +210,17 @@ dependencies {
     debugImplementation(libs.compose.ui.test.manifest)
 }
 
-tasks.withType<Test> { useJUnitPlatform() }
+tasks.withType<Test> {
+    useJUnitPlatform()
+    // Print the assertion message + full stack trace for failures. The
+    // default console output gives only "AssertionError at Foo.kt:12", and
+    // for a failure inside a `runTest { }` lambda even that line collapses
+    // to the test function's own line (the assertion frames live in the
+    // suspend-lambda class, which Gradle filters out) — leaving nothing to
+    // debug from when the HTML report isn't reachable, as in CI.
+    testLogging {
+        events("failed")
+        exceptionFormat = org.gradle.api.tasks.testing.logging.TestExceptionFormat.FULL
+        showStackTraces = true
+    }
+}