chore(authenticator): add Flatpak desktop entry and AppStream metainfo

applications/authenticator/me.proton.Authenticator.desktop

@@ -0,0 +1,9 @@
+[Desktop Entry]
+Name=Proton Authenticator
+Comment=End-to-end encrypted 2FA code manager by Proton
+Exec=proton-authenticator %U
+Icon=me.proton.Authenticator
+Terminal=false
+Type=Application
+Categories=Utility;Security;
+StartupWMClass=Proton Authenticator

applications/authenticator/me.proton.Authenticator.metainfo.xml

@@ -0,0 +1,92 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<component type="desktop-application">
+  <id>me.proton.Authenticator</id>
+  <name>Proton Authenticator</name>
+  <summary>End-to-end encrypted 2FA code manager by Proton</summary>
+  <developer id="me.proton">
+    <name translate="no">Proton AG</name>
+  </developer>
+
+  <metadata_license>CC0-1.0</metadata_license>
+  <project_license>GPL-3.0-only</project_license>
+
+  <description>
+    <p>
+      Proton Authenticator is a free and open-source two-factor authentication
+      (2FA) app from Proton, the company behind Proton Mail and Proton VPN.
+    </p>
+    <p>Features include:</p>
+    <ul>
+      <li>End-to-end encrypted 2FA code storage and sync across devices</li>
+      <li>Automatic backup of your 2FA codes to your Proton account</li>
+      <li>Supports TOTP (time-based one-time passwords)</li>
+      <li>Works offline -- generates codes without an internet connection</li>
+      <li>Import tokens from other authenticator apps</li>
+      <li>Compatible with any website or service that supports 2FA</li>
+    </ul>
+    <p>
+      A free Proton account is required to use the sync and backup features.
+      The app can also be used as a standalone TOTP generator without an account.
+    </p>
+  </description>
+
+  <url type="homepage">https://proton.me/authenticator</url>
+  <url type="bugtracker">https://github.com/ProtonMail/WebClients/issues</url>
+  <url type="vcs-browser">https://github.com/ProtonMail/WebClients</url>
+  <url type="help">https://proton.me/support/authenticator</url>
+
+  <launchable type="desktop-id">me.proton.Authenticator.desktop</launchable>
+
+  <branding>
+    <color type="primary" scheme_preference="light">#6D4AFF</color>
+    <color type="primary" scheme_preference="dark">#3B24CC</color>
+  </branding>
+
+  <requires>
+    <control>keyboard</control>
+    <control>pointing</control>
+    <display_length compare="ge">768</display_length>
+  </requires>
+
+  <content_rating type="oars-1.1">
+    <content_attribute id="social-info">mild</content_attribute>
+  </content_rating>
+
+  <releases>
+    <release version="1.1.4" date="2025-09-15">
+      <url type="details">https://github.com/ProtonMail/WebClients/blob/main/applications/authenticator/CHANGELOG.md</url>
+      <description>
+        <p>Bug fixes and stability improvements.</p>
+      </description>
+    </release>
+    <release version="1.1.3" date="2025-09-08">
+      <description>
+        <p>Bug fixes and stability improvements.</p>
+      </description>
+    </release>
+    <release version="1.1.2" date="2025-09-05">
+      <description>
+        <p>Bug fixes and stability improvements.</p>
+      </description>
+    </release>
+    <release version="1.1.1" date="2025-09-03">
+      <description>
+        <p>Bug fixes and stability improvements.</p>
+      </description>
+    </release>
+    <release version="1.1.0" date="2025-09-02">
+      <description>
+        <p>New features and improvements.</p>
+      </description>
+    </release>
+    <release version="1.0.0" date="2025-07-31">
+      <description>
+        <p>Initial release of Proton Authenticator for Linux.</p>
+      </description>
+    </release>
+  </releases>
+
+  <provides>
+    <binary>proton-authenticator</binary>
+  </provides>
+</component>