v1.0.0-rc.12

• Fixed the local VPN completing an app's TCP handshake before its protected upstream connection
  succeeded. An unreachable IPv6 destination could appear connected and prevent the app from trying
  a working IPv4 address. The VPN now connects upstream first and rejects failed connections before
  acknowledging them, while retaining IPv4 and IPv6 support.
• VPN shutdown cancels pending TCP connections, closes upstream sockets, and waits for endpoint
  registration before shutting down the network stack. TCP half-close preserves the server's
  response after the client finishes sending.
• Added IPv4/IPv6 packet-level regressions for handshake ordering, rejected connections, complete
  bidirectional transfers, half-close, and cancellation during connection setup and shutdown.
  UDP round-trip tests verify complete packets and shaping transitions. The Android host harness
  now requires a complete VPN download; failed transfers and skipped scenarios cannot count as a pass.

Application update from v1.0.0-rc.11: retain any required research exports, then install the
signed RC12 APK over the existing app without uninstalling. The application ID and production
signing certificate are unchanged, and the Android version code increases.

Local studies and exported data: RC12 introduces no local-store migration, mandatory reset,
or event-source-registry change from RC11. Existing signed configurations and local study data remain
in place. Reopen the app after updating, complete normal recovery and access checks, and explicitly
Resume the study. Installing the APK does not change a study's collectors, schedule, consent, or
questionnaire. The restrictions for older configurations documented in earlier releases still apply.

Fresh install: install the signed RC12 APK, then scan a research-team QR code or import its
signed study file. Review the study and data collection, provide consent, complete required access
setup, and explicitly Start.

Verification scope: this prerelease uses a locally built production-signed APK with version
code 39. Native Go race tests and vet, host unit tests, debug/release lint, and APK signing and
native-packaging verification passed. The remote API 34 complete functional gate and Web, receiver,
and analysis consumer checks also passed. Packet tests include a complete 256 KiB download through
the capped all-App VPN. The user reported restored browsing on a Pixel 10a running Android 16 after
an ADB update of the production-signed repair.

The remote API 37 x86_64 / 16 KiB gate was blocked before instrumentation by the existing
SurfaceFlinger / mapper.ranchu.so DMA-capability assertion on image revision 6 and emulator
37.1.11. Its three APK-install attempts failed with a package-service broken pipe, so the automated
publish job was skipped. Separate API 37 / 16 KiB ARM64 compatibility instrumentation passed on the
Play Store image revision 4; this does not establish a pass for the remote x86_64 lane or its full
host harness. See the RC12 workflow evidence.