feat(panic): FUCK [panic] mode=strict|fallback + realtest image variant

- UTSM panic_full returns in fallback mode (logs [PANIC:FALLBACK] + code + hit
  count); panic_halt keeps always-halt sites (CPU exception, VMM-E11 LA57,
  VMM-E15 DSK jump, UTSM-E42 test hook). Call sites given safe continuations.
- Mode passed to DSK/FirstInit/login/desktop via DSK_BOOT_FLAG_PANIC_FALLBACK;
  DKM kernel_api.panic / kern.log.panic return to driver; ext4 fatal aborts the
  op via setjmp/longjmp and DSK falls back to FAT32 ESP.
- build.ps1/Makefile: dev=strict, release=fallback, new realtest (release
  options + strict); default -Variant all; serialized iso packing under -j.
- Fix '*/' inside comments (dkm.h, kernel_api.h, bus.c) that broke the build.
- Includes pending work: dkm_bus service bus, mt7920/wlan drivers, desktop
  files/startmenu/prank, pe-tools, diskinfo, docs.

Co-authored-by: Cursor <cursoragent@cursor.com>

CODE/UTSM/include/utsm/dsk.h

@@ -10,6 +10,9 @@
 #define DSK_BOOT_FLAG_DKM_READY       (1ULL << 1)
 #define DSK_BOOT_FLAG_FAT32_PATH      (1ULL << 2)
 #define DSK_BOOT_FLAG_PROBE_INFO      (1ULL << 3)
+/* FUCK [panic] mode=fallback：DSK/desktop/login/FirstInit 的 *_fatal 记录后返回，
+ * 调用点走备用路径（见 utsm/panic.h）。未置位 = strict。 */
+#define DSK_BOOT_FLAG_PANIC_FALLBACK  (1ULL << 4)
 
 /* ---- Probe 信息结构（通过 reserved[6] 传递给 shell/desktop） ---- */
 #define PROBE_INFO_MAGIC 0x50524F42u  /* "PRFB" — Probe inFo Buffer */