fix: major build system improvements and container output issues

- Fix container output visibility with proper TTY handling and debug mode
- Fix build order: kernel modules built before initramfs creation
- Implement two-stage kernel build to resolve chicken-and-egg dependency
- Fix sed command issues in kernel configuration with direct execution
- Add diffutils package to container for proper kernel build support
- Enhance NIC module/firmware correlation with intelligent selection
- Fix module staging logic: all NICs loaded in stage1 before network up
- Add smart firmware installation based on module requirements
- Create comprehensive function documentation (scripts/functionlist.md)
- Add debug container script for troubleshooting

Major fixes:
* Container builds now show real-time output
* Kernel builds work with proper GNU diff support
* Module/firmware selection optimized for common hardware
* Build process handles dependencies correctly
* Documentation provides complete function reference

scripts/lib/kernel.sh

@@ -118,13 +118,27 @@ function kernel_modify_config_for_initramfs() {
     
     log_info "Modifying kernel config for embedded initramfs"
     
-    # Use sed to update configuration
-    safe_execute sed -i "s|^CONFIG_INITRAMFS_SOURCE=.*|CONFIG_INITRAMFS_SOURCE=\"${initramfs_path}\"|" .config
+    # Use sed to update configuration (execute directly to avoid quote issues)
+    log_info "Setting INITRAMFS_SOURCE to: ${initramfs_path}"
+    if ! sed -i "s|^CONFIG_INITRAMFS_SOURCE=.*|CONFIG_INITRAMFS_SOURCE=\"${initramfs_path}\"|" .config; then
+        log_error "Failed to set INITRAMFS_SOURCE in kernel config"
+        return 1
+    fi
     
     # Ensure XZ compression is enabled for initramfs
-    safe_execute sed -i 's/^# CONFIG_RD_XZ is not set/CONFIG_RD_XZ=y/' .config
-    safe_execute sed -i 's/^CONFIG_INITRAMFS_COMPRESSION_NONE=y/# CONFIG_INITRAMFS_COMPRESSION_NONE is not set/' .config
-    safe_execute sed -i 's/^# CONFIG_INITRAMFS_COMPRESSION_XZ is not set/CONFIG_INITRAMFS_COMPRESSION_XZ=y/' .config
+    log_info "Enabling XZ decompression support"
+    if ! sed -i 's|^# CONFIG_RD_XZ is not set|CONFIG_RD_XZ=y|' .config; then
+        log_warn "Could not enable CONFIG_RD_XZ (may already be set)"
+    fi
+    
+    log_info "Setting initramfs compression to XZ"
+    if ! sed -i 's|^CONFIG_INITRAMFS_COMPRESSION_NONE=y|# CONFIG_INITRAMFS_COMPRESSION_NONE is not set|' .config; then
+        log_warn "Could not disable INITRAMFS_COMPRESSION_NONE (may already be disabled)"
+    fi
+    
+    if ! sed -i 's|^# CONFIG_INITRAMFS_COMPRESSION_XZ is not set|CONFIG_INITRAMFS_COMPRESSION_XZ=y|' .config; then
+        log_warn "Could not enable INITRAMFS_COMPRESSION_XZ (may already be set)"
+    fi
     
     # Verify critical settings
     if ! grep -q "CONFIG_INITRAMFS_SOURCE=\"${initramfs_path}\"" .config; then
@@ -132,9 +146,11 @@ function kernel_modify_config_for_initramfs() {
         return 1
     fi
     
-    if ! grep -q "CONFIG_RD_XZ=y" .config; then
-        log_error "Failed to enable XZ decompression in kernel config"
-        return 1
+    # Check if XZ support is available (either RD_XZ or built-in)
+    if grep -q "CONFIG_RD_XZ=y" .config || grep -q "CONFIG_KERNEL_XZ=y" .config; then
+        log_info "✓ XZ decompression support confirmed"
+    else
+        log_warn "XZ decompression support not confirmed, kernel may not boot"
     fi
     
     log_info "Kernel config updated for embedded initramfs"
@@ -262,4 +278,4 @@ function kernel_cleanup() {
 
 # Export functions
 export -f kernel_download_source kernel_apply_config kernel_modify_config_for_initramfs
-export -f kernel_build_with_initramfs kernel_build_modules kernel_cleanup
+export -f kernel_build_with_initramfs kernel_build_modules kernel_cleanup