Bring the checklist app under version control

The project has lived only as a folder on the Mac Studio and, briefly, as a
transfer tarball. This is the first commit: the Express server and its web
front end, the Capacitor iOS and Android wrappers, and the release and backup
scripts.

The repo is the source, not a backup of the machine. Left out on purpose, by
the .gitignore files that were already in the tree: node_modules, build output,
mobile/www (regenerated from server/public on every build), and server/data,
which holds the live checklists and belongs on the NAS rather than in git.

Every credential is excluded too — server/.env, the Play upload keystore and
its properties file, the App Store Connect key and ios-signing.config. The one
secret that was not in an ignored file was the NAS SSH password, hard-coded in
build-deploy.sh and grepped back out of it by backup-to-drive.sh. Both now read
it from the login keychain (service checklist-nas, account Christian), falling
back to NAS_PASS in the environment, so rotating it is one keychain entry
rather than a history rewrite.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

mobile/android/app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile