V3-12: crash reporting (code only)

shouldInitializeCrashReporting() and scrubExtra() are pure, fully unit-tested decision/scrubbing functions wired into sentry_flutter via beforeSend/beforeBreadcrumb. Config.crashReportingEnabled defaults off; the DSN is a compile-time --dart-define, not a preference. RecordingEngine gained an injected onUnexpectedStop callback, firing once when restoreAfterProcessDeath finds a trip still 'recording' at launch -- the process died without a user stop.

Marked partially done: the ticket's real acceptance criteria (a forced crash landing in a real Sentry project from a release build, inspecting a real payload) need a Sentry account and a release build this environment can't produce.

pubspec.lock

@@ -887,6 +887,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.6.1"
+  sentry:
+    dependency: transitive
+    description:
+      name: sentry
+      sha256: "599701ca0693a74da361bc780b0752e1abc98226cf5095f6b069648116c896bb"
+      url: "https://pub.dev"
+    source: hosted
+    version: "8.14.2"
+  sentry_flutter:
+    dependency: "direct main"
+    description:
+      name: sentry_flutter
+      sha256: "5ba2cf40646a77d113b37a07bd69f61bb3ec8a73cbabe5537b05a7c89d2656f8"
+      url: "https://pub.dev"
+    source: hosted
+    version: "8.14.2"
   share_plus:
     dependency: "direct main"
     description: