fix(rancher-desktop): fix builddir lint errors

Three issues from the builddir lint step:
- appstream-missing-developer-name: add <developer> tag to metainfo.xml
- appstream-failed-validation (desktop-app-launchable-missing): add
  <launchable> tag to metainfo.xml
- elf-arch-multiple-found: upstream zip bundles both x86_64 and aarch64
  native Node modules; add to exceptions.json

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: castrojo

flatpaks/rancher-desktop/GOTCHAS.md

@@ -59,3 +59,16 @@ step validates that icons in `hicolor/512x512/` are ≤512×512 and rejects the
 
 Fix: use `python3` + GdkPixbuf (available in GNOME SDK 49) to resize the icon to 512×512 before
 installing it. Do **not** use `install -Dm644` directly — that copies the oversized file as-is.
+
+## elf-arch-multiple-found lint exception
+The upstream zip bundles native Node modules for both x86_64 and aarch64 (e.g.
+`posix-node/dist/aarch64-linux-gnu.node` alongside `x86_64-linux-gnu.node`).
+flatpak-builder-lint flags this as `elf-arch-multiple-found`. It is intentional and
+structural — the upstream ships a fat zip with multi-arch native modules. Added to
+`exceptions.json`.
+
+## appstream-missing-developer-name / appstream-failed-validation fixes
+The upstream metainfo.xml does not include `<developer>` or `<launchable>` tags.
+Both have been added to `io.rancherdesktop.RancherDesktop.metainfo.xml`:
+- `<developer><name>SUSE LLC</name></developer>`
+- `<launchable type="desktop-id">io.rancherdesktop.RancherDesktop.desktop</launchable>`

flatpaks/rancher-desktop/exceptions.json

@@ -5,6 +5,7 @@
         "metainfo-missing-screenshots",
         "finish-args-home-filesystem-access",
         "finish-args-flatpak-spawn-access",
-        "finish-args-host-os-ro-filesystem-access"
+        "finish-args-host-os-ro-filesystem-access",
+        "elf-arch-multiple-found"
     ]
 }

flatpaks/rancher-desktop/io.rancherdesktop.RancherDesktop.metainfo.xml

@@ -20,6 +20,8 @@
   <url type="bugtracker">https://github.com/rancher-sandbox/rancher-desktop/issues</url>
   <metadata_license>MIT</metadata_license>
   <project_license>Apache-2.0</project_license>
+  <developer><name>SUSE LLC</name></developer>
+  <launchable type="desktop-id">io.rancherdesktop.RancherDesktop.desktop</launchable>
   <categories>
     <category>Development</category>
     <category>Utility</category>