Replace the app-local crash machinery (CrashReporter, CrashReportDialog,
CrashReportSubmit) with floret-kit's core-crash. The kit version is the same
privacy-respecting, on-device, no-network design (clipboard + prefilled issue
URL via ACTION_VIEW), parameterised by a CrashConfig: app label + the
issue-tracker URLs, supplied once at install() in CalendulaApp.
- CrashReportActivity stays app-local (thin standalone surface) but now imports
the kit's CrashReporter/CrashReportDialog/submitCrashReport.
- buildCrashReport moved to the kit and gained an appLabel parameter; the
privacy-allowlist test is repointed to the kit API (still pins Calendula's
exact six-line header — no identifiers, no calendar content).
- Calendula keeps its own crash strings (incl. German + "calendar content"
wording) as resource overrides, converted to the kit's %1$s app-label /
two-arg body-template arity so the shared code formats them correctly.
Compile + unit tests + lintDebug green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>