chore(quality): detekt, lint, and proguard audit (v2.1.0)

Detekt: 0 issues.
Lint: suppressed GradleDependency (batch updates per minor release);
fixed illegal XML comment delimiter (-- before >) in lint.xml that
caused 4 spurious parse-error warnings.
ktlint: 0 violations.
Unit tests: all passed.
Release build (ProGuard): successful, APK 5.0 MB.

Author: inventory69

android/app/lint.xml

@@ -59,4 +59,11 @@
     <!-- → Migration geplant für v2.1.0                             -->
     <!-- ═══════════════════════════════════════════════════════════ -->
     <issue id="AndroidGradlePluginVersion" severity="ignore" />
+
+    <!-- ═══════════════════════════════════════════════════════════ -->
+    <!-- GradleDependency: Dependency-Updates werden bewusst         -->
+    <!-- batchweise in neuen Minor-Releases durchgeführt, nicht      -->
+    <!-- inkrementell pro Patch-Release (zu hohes Regressionsrisiko).-->
+    <!-- ═══════════════════════════════════════════════════════════ -->
+    <issue id="GradleDependency" severity="ignore" />
 </lint>