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/debug-container.sh

@@ -0,0 +1,59 @@
+#!/bin/bash
+# Debug script to test container output behavior
+
+set -euo pipefail
+
+# Script directory and project root detection
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(dirname "$SCRIPT_DIR")"
+
+echo "=== HOST DEBUG TEST ==="
+echo "SCRIPT_DIR: $SCRIPT_DIR"
+echo "PROJECT_ROOT: $PROJECT_ROOT"
+echo "PWD: $(pwd)"
+echo "USER: $(whoami)"
+
+# Source common functions
+source "${SCRIPT_DIR}/lib/common.sh"
+
+echo "=== AFTER SOURCING COMMON.SH ==="
+log_info "Testing log_info function"
+log_warn "Testing log_warn function"
+log_error "Testing log_error function"
+
+echo "=== TESTING SAFE_EXECUTE ==="
+safe_execute echo "Testing safe_execute with simple command"
+safe_execute ls -la "${SCRIPT_DIR}"
+
+echo "=== TESTING IN_CONTAINER ==="
+if in_container; then
+    log_info "Running inside container"
+else
+    log_info "Running on host"
+fi
+
+echo "=== CHECKING DOCKER FUNCTIONS ==="
+source "${SCRIPT_DIR}/lib/docker.sh"
+
+if command_exists "podman" || command_exists "docker"; then
+    log_info "Container runtime available, testing container run"
+    
+    docker_detect_runtime
+    
+    # Test minimal container run
+    log_info "Testing minimal container echo"
+    if [[ -n "${CONTAINER_RUNTIME:-}" ]]; then
+        echo "Running: ${CONTAINER_RUNTIME} run --rm alpine:3.22 echo 'Container test successful'"
+        ${CONTAINER_RUNTIME} run --rm alpine:3.22 echo "Container test successful"
+        
+        echo "Running: ${CONTAINER_RUNTIME} run --rm alpine:3.22 sh -c 'echo First line; echo Second line; echo Third line'"
+        ${CONTAINER_RUNTIME} run --rm alpine:3.22 sh -c 'echo First line; echo Second line; echo Third line'
+        
+        echo "Testing with TTY:"
+        ${CONTAINER_RUNTIME} run --rm -it alpine:3.22 sh -c 'echo TTY test line 1; echo TTY test line 2'
+    fi
+else
+    log_warn "No container runtime available"
+fi
+
+echo "=== DEBUG TEST COMPLETE ==="