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

[the-narwhal]

What

Adds two files to applications/authenticator/ to support the Flatpak packaging of Proton Authenticator on Flathub:

• me.proton.Authenticator.desktop — XDG desktop entry (app launcher integration on Linux)
• me.proton.Authenticator.metainfo.xml — AppStream metadata (description, OARS content rating, branding colours, release history) used by the Flathub store listing and GNOME Software

Why here

The Flathub submission guidelines require that .desktop and .metainfo.xml files be maintained in the upstream source repository rather than in the Flathub manifest repo. The Flatpak build installs them with explicit install commands — no changes to the existing build system are needed.

What this doesn't do

• No changes to any existing file
• No effect on the npm/Yarn/Tauri build pipeline
• No new runtime dependencies

Related

• Flathub submission: Add me.proton.Authenticator flathub/flathub#8359
• Upstream notification issue: Proton Authenticator submitted to Flathub #482

[the-narwhal]

@D-Bao ,

Quick status update on the Flathub submission, the proton-authenticator@ tags seem to get pruned after a couple of months. The 1.1.5 and 1.1.6 tags are gone now. I'll update the flathub submission once the next tag is published.

Metainfo and desktop entry

A few things I'm currently working around in the Flathub manifest that would be better fixed here:

1.Flathub requires at least one, and the build linter fails without them. For now I'm patching in the Authenticator image from proton.me. If you have official screenshots you'd prefer, they could go in the metainfo directly.
2. StartupWMClass: on Linux the Tauri window's app_id is the binary name, proton-authenticator, so StartupWMClass=Proton Authenticator doesn't match. GNOME and KDE then show a generic icon for the running window.
3. appstreamcli validate --strict suggests moving the keyboard/pointing controls from to , since requires is meant for hard installation requirements.

I've also opened #545 for the single-instance D-Bus name. In the Flatpak sandbox, a second launch currently opens a second window instead of focusing the running one.