chore: Auto-request mobile team review on public API changes

Add CODEOWNERS rules for the committed binary-compatibility-validator
baselines of the public SDK API surface (sentry/api/sentry.api and
sentry-android-core/api/sentry-android-core.api). They only change when
the public API changes, so @getsentry/team-mobile is now auto-requested
as a reviewer on API changes consumed by the hybrid mobile SDKs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: antonis

.github/CODEOWNERS

@@ -1 +1,5 @@
 *       @adinauer @romtsn @markushi @runningcode @0xadam-brown
+
+# Public API surface — auto-request a mobile SDK team review on API changes
+/sentry/api/sentry.api @getsentry/team-mobile
+/sentry-android-core/api/sentry-android-core.api @getsentry/team-mobile