fix: Switch to space-separated sources.conf format

- Change from colon to space separation to avoid URL parsing issues
- Update sources.conf format: TYPE NAME URL VERSION BUILD_FUNCTION [EXTRA]
- Implement awk-based parsing for reliable field extraction
- Fix firmware package list (remove unavailable linux-firmware-marvell)

scripts/lib/alpine.sh

@@ -345,8 +345,13 @@ export TERM=xterm
 umask 022
 EOF
     
-    # Set root shell
-    safe_execute chroot "$initramfs_dir" chsh -s /bin/sh root
+    # Set root shell (if chsh is available)
+    if chroot "$initramfs_dir" which chsh >/dev/null 2>&1; then
+        safe_execute chroot "$initramfs_dir" chsh -s /bin/sh root
+    else
+        log_info "chsh not available in minimal Alpine, skipping shell change"
+        log_info "Root shell defaults to /bin/sh in Alpine"
+    fi
     
     log_info "Alpine system configuration complete"
 }