build(android): install the debug build alongside release as its own app

Testing a debug build meant uninstalling the real one first: same
applicationId signed with a different key is INSTALL_FAILED_UPDATE_
INCOMPATIBLE, so every experiment cost the app's settings, credentials
and offline cache.

The debug build type now carries applicationIdSuffix ".debug" and
versionNameSuffix "-debug", so it installs as com.dtourolle.jellytau.debug
("JellyTau Debug", 0.5.5-debug) with its own data directory — two
independent apps on one device.

Only the *application* id is suffixed. Kotlin classes stay in the
`namespace` package com.dtourolle.jellytau, so the JNI loadClass lookups
in player/android/mod.rs, the manifest <service> entry and the R8 keep
rules are untouched, and the FileProvider authority was already
${applicationId}-relative. Launcher names come from the appLabel /
activityLabel manifestPlaceholders rather than resValue, which would
collide with Tauri's generated strings.xml; release resolves them back to
@string/app_name and merges byte-identical.

deploy-android.sh reports the target package and explains an
UPDATE_INCOMPATIBLE failure instead of leaving it raw; logcat.sh takes a
debug|release argument (it was filtering on com.jellytau.app, a package
that has never existed) and attaches by pid when the app is running.

Verified: aapt2 badging on the built APK reports
com.dtourolle.jellytau.debug / 0.5.5-debug / "JellyTau Debug", and the
release manifest merge is unchanged.

scripts/logcat.sh

@@ -1,13 +1,34 @@
 #!/bin/bash
-# View Android logcat output filtered for the app
+# View Android logcat output filtered for the app.
+#
+# Usage: ./scripts/logcat.sh [debug|release]   (default: debug)
+#
+# The debug build has applicationIdSuffix ".debug" so it can be installed
+# alongside a release build; pick the package to follow accordingly.
 
 set -e
 
-APP_PACKAGE="com.jellytau.app"
+BUILD_TYPE="${1:-debug}"
+
+if [ "$BUILD_TYPE" = "release" ]; then
+    APP_PACKAGE="com.dtourolle.jellytau"
+else
+    APP_PACKAGE="com.dtourolle.jellytau.debug"
+fi
 
 echo "📱 Showing logcat for $APP_PACKAGE"
 echo "Press Ctrl+C to stop"
 echo ""
 
-# Filter logcat for the app's package name
-adb logcat | grep -i "$APP_PACKAGE\|tauri\|rust"
+# Prefer PID-scoped output when the app is running — it drops the noise that a
+# text grep can't. Fall back to the old keyword filter when it isn't (so you can
+# start the script first and then launch the app).
+PID="$(adb shell pidof "$APP_PACKAGE" 2>/dev/null | tr -d '\r\n' | awk '{print $1}')"
+
+if [ -n "$PID" ]; then
+    echo "   (attached to pid $PID)"
+    adb logcat --pid="$PID"
+else
+    echo "   (app not running — falling back to keyword filter)"
+    adb logcat | grep -i "$APP_PACKAGE\|jellytau\|tauri\|rust"
+fi