feat(git-lfs): add Git LFS status and sidecar bundling

Adds Git LFS support to the backend API and related UI.
The app now exposes commands to inspect, install, track and pull.
A sidecar git-lfs binary is bundled and a prep script is added.
This prepares the correct binary for each target platform.

- Expose Git LFS status and management commands in API
- Bundle and prepare a sidecar git-lfs binary for targets
- Update packaging, docs, and README with LFS notes

.gitea/workflows/app_builder.yaml

@@ -161,7 +161,7 @@ jobs:
             >> /etc/pacman.d/mirrorlist
 
           ARCH_PACKAGES=(
-            base-devel curl git nodejs npm openssh rust
+            base-devel curl git git-lfs nodejs npm openssh rust
             webkit2gtk-4.1 gtk3 hicolor-icon-theme
             libappindicator-gtk3 librsvg xdotool
           )
@@ -486,7 +486,7 @@ jobs:
       - name: Install Ubuntu dependencies
         run: |
           sudo apt-get update
-          sudo apt-get install -y build-essential curl wget file libssl-dev libwebkit2gtk-4.1-dev libayatana-appindicator3-dev librsvg2-dev patchelf libxdo-dev libfuse2
+          sudo apt-get install -y build-essential curl wget file git-lfs libssl-dev libwebkit2gtk-4.1-dev libayatana-appindicator3-dev librsvg2-dev patchelf libxdo-dev libfuse2
 
       - name: Setup Node
         uses: actions/setup-node@v4