android: the keep rules, and the release build that proves them

Every APK this port has produced is `assembleArm64Debug`, and the generated
project turns R8 on for `release` and only for `release` — while tauri finds a
plugin class by string, files every `@Command` under `commands[method.name]`,
and lets Jackson fill every `@InvokeArg` field by field. Minification breaks
exactly that, and it breaks it without a word: the app compiles, installs,
launches, shows Home, and then a tap on Library folder answers "No command
pickFolder found for plugin ..." in logcat and nothing on screen. So each
plugin module now carries its own `consumer-rules.pro` naming its own
reflected surface — the shape tauri-android and tauri-plugin-dialog already
use in this build, and one that travels with the plugin into a regenerated
`gen/android`, which a rule written into that gitignored tree would not.

What belongs to no single plugin is in `src-tauri/android/proguard-soulstream.pro`,
copied into the generated project by the build script because the app's own
Gradle file is regenerated: the runtime annotation attributes, a `-dontwarn`
pair for the two `java.beans` classes jackson-databind references and Android
does not have (R8 turns a missing class into a build error, so without them
there may be no APK at all), and a keep for the four `@Command` methods
declared on `app.tauri.plugin.Plugin` itself. Tauri's own rule matches classes
annotated `@TauriPlugin` and the members they declare; the base class carries
no such annotation, so nothing names `registerListener` — which is what the
lock-screen card's buttons and the download notice's Cancel and Open ride on.

`build.sh` grows `--release`: the release profile, `--features tauri/devtools`
so the walk can still attach at all, `assembleArm64Release`, and a zipalign and
sign with the same debug key the phone already trusts, so the APK installs over
the app rather than forcing an uninstall that would take Kyle's settings with
it. With no argument the script is what it has always been, cargo line for
cargo line, so deploy.sh and ship.sh keep the path they run every twenty
minutes. And it has been built. Not on the phone and not as arm64 — as **x86_64**, on an
emulator, because that is what this machine can run — but the flavour is the
only difference: the same Gradle, the same R8, the same rules, the same
zipalign and apksigner. `minifyX86_64ReleaseWithR8` succeeded and wrote **no**
`missing_rules.txt` at all, which is the `-dontwarn` pair doing its job;
`lintVitalX86_64Release` passed, so the `-x lintVital` advice is for a failure
that has not happened. The signed APK went over the debug app with
`adb install -r` and left its data alone, exactly as the same-key argument
above says it must.

Then the minified app was walked: Home, the record, playback, the queue, the
sheets, the lyrics, the drags, the export — **131 of 131, no exceptions, no
console errors, every step as expected**, and nothing in logcat about a missing
command or class. That is the failure this round exists to prevent, looked for
and not found.

What it does not cover is the hands-only list in ANDROID.md — the pickers, the
notification buttons, the share sheet — which no walk reaches, and the four
`@Command` methods on `Plugin` itself remain a precaution rather than a
diagnosed bug. The document says so, command by command.

crates/tauri-plugin-transfer-notice/android/build.gradle.kts

@@ -9,6 +9,10 @@ android {
 
     defaultConfig {
         minSdk = 26
+        // the plugin's own R8 keep rules, handed to whatever app links this
+        // module — inert unless that app minifies, which only the release
+        // build type does
+        consumerProguardFiles("consumer-rules.pro")
     }
 
     compileOptions {