Fix init script setup and preserve build artifacts

- Copy configs/init as /sbin/init instead of creating symlink to zinit
- Remove automatic cleanup of build artifacts - always preserve for incremental builds
- Allows rebuilding initramfs with existing components
- Use ./scripts/clean.sh to manually clean when needed

scripts/lib/initramfs.sh

@@ -27,10 +27,18 @@ function initramfs_setup_zinit() {
         return 1
     fi
     
-    # Remove existing init (if any) and replace with zinit
-    log_info "Replacing system init with zinit"
+    # Copy configs/init as /sbin/init (not a symlink to zinit)
+    log_info "Installing configs/init as /sbin/init"
     safe_execute rm -f "${initramfs_dir}/sbin/init"
-    safe_execute ln -sf zinit "${initramfs_dir}/sbin/init"
+    local configs_init="${PROJECT_ROOT}/configs/init"
+    if [[ -f "$configs_init" ]]; then
+        safe_execute cp "$configs_init" "${initramfs_dir}/sbin/init"
+        safe_execute chmod 755 "${initramfs_dir}/sbin/init"
+        log_info "✓ Installed configs/init as /sbin/init"
+    else
+        log_error "configs/init not found: $configs_init"
+        return 1
+    fi
     
     # Copy zinit configuration (all YAML and scripts)
     log_info "Installing zinit configuration"