Add Gitea CI + release workflows (CI-SETUP.md)

- .gitea/workflows/ci.yml: gateway plugin tests + Kotlin host tests on
  push/PR (hermes-agent cloned at pinned SHA, vendored test mirror)
- .gitea/workflows/release.yml: manual dispatch; runs tests, builds signed
  Android APK (debug fallback) + Linux desktop app-image/deb via jpackage,
  creates Gitea release v<version> with artifacts (re-run safe)
- androidApp: versionName from -PappVersion, CI release signing from
  ANDROID_KEYSTORE_* env vars
- desktopApp: jpackage --app-version from -PappVersion
- scripts/make_release_keystore.sh: one-time keystore + Gitea secret setup
- vendor gateway-plugin/tests/test_android.py (byte-identical mirror) and
  ignore it in .pi-lens.json

scripts/make_release_keystore.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+# One-time setup: create the Android release keystore and print the values to
+# paste into Gitea (repo -> Settings -> Actions -> Secrets).
+#
+# Usage:  scripts/make_release_keystore.sh [output-file]
+#         (default: ~/iris-release.keystore)
+#
+# WARNING: back up the keystore file immediately. If it is lost, the app can
+# never be updated on users' phones (a new key = a brand-new app as far as
+# Android is concerned).
+set -euo pipefail
+
+OUT="${1:-$HOME/iris-release.keystore}"
+if [ -e "$OUT" ]; then
+  echo "Refusing to overwrite existing file: $OUT" >&2
+  exit 1
+fi
+
+STORE_PASS="$(openssl rand -base64 18 | tr -d '/+=')"
+KEY_PASS="$(openssl rand -base64 18 | tr -d '/+=')"
+
+keytool -genkeypair -v \
+  -keystore "$OUT" -storetype PKCS12 \
+  -alias iris -keyalg RSA -keysize 2048 -validity 10000 \
+  -storepass "$STORE_PASS" -keypass "$KEY_PASS" \
+  -dname "CN=Iris Release, OU=Mobile, O=Iris, C=DE"
+
+echo
+echo "Keystore written to: $OUT"
+echo ">>> Back it up NOW (password manager / cloud storage). <<<"
+echo
+echo "Add these four secrets in Gitea (repo -> Settings -> Actions -> Secrets):"
+echo
+echo "  ANDROID_KEYSTORE_BASE64   = $(base64 -w0 "$OUT")"
+echo
+echo "  ANDROID_KEYSTORE_PASSWORD = $STORE_PASS"
+echo "  ANDROID_KEY_ALIAS         = iris"
+echo "  ANDROID_KEY_PASSWORD      = $KEY_PASS"