Fix tmux AppImage install for FUSE-less environments

Codespaces doesn't have FUSE, so the AppImage can't run directly.
Extract the binary from the AppImage at install time using
--appimage-extract and install just the tmux binary to ~/.local/bin.

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

Author: tarebyte

script/install-codespace-tools

@@ -139,8 +139,11 @@ else
   echo "  Installing tmux..."
   gh release download --clobber --output /tmp/tmux.appimage --repo nelsonenzo/tmux-appimage \
     --pattern "tmux.appimage"
-  install /tmp/tmux.appimage "$LOCAL_BIN/tmux"
-  rm -f /tmp/tmux.appimage
+  chmod +x /tmp/tmux.appimage
+  cd /tmp && /tmp/tmux.appimage --appimage-extract >/dev/null 2>&1
+  install /tmp/squashfs-root/usr/bin/tmux "$LOCAL_BIN/tmux"
+  rm -rf /tmp/tmux.appimage /tmp/squashfs-root
+  cd - >/dev/null
   echo "  ✓ tmux installed ($(tool_version tmux), $((SECONDS - start))s)"
 fi