Prepare Android release artifacts and listing (#112)

Add Rust distribution auditing, pinned post-build AAB signing, complete offline third-party notices, an Android privacy policy and reviewable Play listing assets. Preserve the application ID and audit both ARM ABIs, native symbols, baseline profiles and R8 mapping.

Fix dialog focus ownership, navigation-triggered cleanup loops and stale authentication errors after first-run setup, with native and real-activity regressions.

Google Play publication is deferred by the user. Issue #112 remains open for production signing, Console declarations and actual Play install/update verification.

android/licenses/checker-qual.txt

@@ -0,0 +1,22 @@
+Checker Framework qualifiers
+Copyright 2004-present by the Checker Framework developers
+
+MIT License:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.