build(android): release signing + mirror/JDK setup; native-feel CSS

- Release signing via android/keystore.properties (git-ignored); build.gradle
  signs release builds when the props file is present, stays unsigned otherwise.
- android/mirror-init.gradle: injects the myket.ir Maven mirror into every
  project's buildscript (dl.google.com is unreachable here) and pins Build-Tools
  to the installed 36.0.0. Build with:
    gradlew assembleRelease bundleRelease -I mirror-init.gradle
  (JAVA_HOME must point at a JDK 21 — Capacitor 8 compiles against Java 21.)
- gitignore keystores, keystore.properties, and /dist artifacts.
- Native-app feel: kill tap-highlight, long-press callout, and stray text
  selection (inputs/messages opt back in); touch-action: manipulation.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/globals.css

@@ -107,6 +107,25 @@ body {
   overscroll-behavior: none;
 }
 
+/* Native-app feel: no blue tap flashes, no long-press callout, no accidental
+   text selection on UI chrome (inputs/messages opt back in below). */
+* {
+  -webkit-tap-highlight-color: transparent;
+}
+body {
+  -webkit-touch-callout: none;
+  -webkit-user-select: none;
+  user-select: none;
+  touch-action: manipulation; /* kill the 300ms double-tap-to-zoom delay */
+}
+input,
+textarea,
+[contenteditable="true"],
+.select-text {
+  -webkit-user-select: text;
+  user-select: text;
+}
+
 body {
   background:
     radial-gradient(120% 90% at 50% 18%, var(--felt-center) 0%, var(--felt-mid) 52%, var(--felt-edge) 100%),