Merge debug/prod into single ISO build, fix NVIDIA module loading

## ISO build consolidation
- Remove separate debug/prod split: overlay-debug/, build-debug.sh,
  mkimg.bee_debug.sh, genapkovl-bee_debug.sh all deleted
- Single overlay: iso/overlay/ (was overlay-debug content)
- Single build script: build.sh (SSH, TUI, NVIDIA, vendor tools, bee-release)
- Single mkimage profile: bee (with dropbear, dialog, strace, gcompat, etc.)

## NVIDIA fixes
- Modules now stored at /usr/local/lib/nvidia/ instead of
  /lib/modules/<kver>/extra/nvidia/ — modloop squashfs mounts over that
  path at boot making overlay content there inaccessible
- bee-nvidia init: load via insmod (absolute path), not modprobe
- bee-nvidia init: create libnvidia-ml.so.1/libcuda.so.1 symlinks in /usr/lib/
- build-nvidia-module.sh: always install linux-lts-dev (not conditional) —
  stale 6.6.x headers caused wrong-kernel modules that never loaded at runtime
- build-nvidia-module.sh: create soname symlinks in cache
- KERNEL_VERSION in VERSIONS updated 6.6 → 6.12
- gcompat added to ISO packages (nvidia-smi is a glibc binary on musl Alpine)

## Service ordering
- bee-audit: add `after bee-nvidia` so NVIDIA enrichment always succeeds

## New tooling
- iso/builder/smoketest.sh: SSH smoke test for post-boot ISO validation
- iso/builder/build-gpu-burn.sh: builds gpu_burn vendor binary (CUDA 12.8+)
- vendor/gpu_burn included automatically if placed in iso/vendor/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/builder/mkimg.bee.sh

@@ -1,9 +1,9 @@
 #!/bin/sh
-# Alpine mkimage profile: bee (production)
+# Alpine mkimage profile: bee
 
 profile_bee() {
     title="Bee Hardware Audit"
-    desc="Hardware audit LiveCD (production unattended mode)"
+    desc="Hardware audit LiveCD"
     arch="x86_64"
     hostname="alpine-bee"
     apkovl="genapkovl-bee.sh"
@@ -13,7 +13,8 @@ profile_bee() {
     kernel_addons=""
     initfs_cmdline="modules=loop,squashfs,sd-mod,usb-storage modloop=/boot/modloop-lts quiet"
     initfs_features="ata base cdrom ext4 mmc nvme raid scsi squashfs usb virtio nfit"
-
+    grub_mod="all_video disk part_gpt part_msdos linux normal configfile search search_label efi_gop fat iso9660 cat echo ls test true help gzio multiboot2 efi_uga"
+    syslinux_serial="0 115200"
     apks="
         alpine-base
         linux-lts
@@ -38,10 +39,20 @@ profile_bee() {
         e2fsprogs
         lshw
 
+        dropbear
         openrc
-        ca-certificates
+        libqrencode-tools
         tzdata
-        jq
-        wget
+        ca-certificates
+
+        strace
+        procps
+        lsof
+        file
+        less
+        vim
+        dialog
+
+        gcompat
     "
 }