core-crash: shared on-device crash capture + report dialog

First Android-library module in the kit. Privacy-respecting crash capture
(writes a self-contained, allowlist-only report to private storage, chains to
the platform handler, uploads nothing), startup crash-loop detection, a report
dialog showing the full text before it leaves the device, and an issue-tracker
hand-off. Extracted from Calendula and generalised: app label + issue URLs come
from a CrashConfig supplied at install(); each app keeps its own thin themed
CrashReportActivity. Lean deps (Compose + core-ktx). 3 unit tests on the pure
report builder.

Adds AGP/android-library + compose plugins and the compose/core-ktx libs to the
kit catalog; core-time stays a plain JVM module.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

build.gradle.kts

@@ -3,6 +3,8 @@
 // consuming apps can depend on `de.jeanlucmakiola.floret:<module>` and Gradle's
 // composite-build substitution maps it to the local source module.
 plugins {
+    alias(libs.plugins.android.library) apply false
+    alias(libs.plugins.kotlin.compose) apply false
     alias(libs.plugins.kotlin.jvm) apply false
 }