terra: cosmic portals, jupiter smb mount, tea CLI, launcher/theme polish

- swap gtk portal/apps for cosmic (xdg-desktop-portal-cosmic, cosmic-files,
  cosmic-settings) and drop dolphin/protonplus/bambu-studio (bambu-studio
  moved to flatpak alongside the other comms/gaming flatpaks)
- mount jupiter's samba share at /mnt/jupiter (automount, credentials from
  the same samba_password secret jupiter itself uses)
- add tea (gitea's remote API CLI) for talking to git.mgaction.town from
  terra without SSHing into jupiter
- new dark icon themes (Amy, Azure Glassy, Slot Beauty) vendored from
  gnome-look.org tarballs, packaged since pling download links expire
- rishot: fix Qt5Compat.GraphicalEffects QML import (was missing qt6.qt5compat
  on QML_IMPORT_PATH, so quickshell failed at config-load)
- launcher widgets: stop LauncherConsole/LauncherDock from reserving
  compositor space (ExclusionMode.Ignore, they're overlays not real docks);
  bump LauncherCorner app icon size 28->34
- comms script: launch telegram/discord via flatpak, not native binaries
- nix-ld + boot.binfmt aarch64 emulation (for building/flashing mercury
  from terra)

dotfiles/quickshell/widgets/launcher/LauncherCorner.qml

@@ -649,7 +649,7 @@ Scope {
                             spacing: 12
 
                             IconImage {
-                                implicitSize: 28
+                                implicitSize: 34
                                 source: Quickshell.iconPath(appRow.modelData.icon, "application-x-executable")
                             }