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/desktop/compositor.c

@@ -171,6 +171,9 @@ void redraw_all(void) {
     /* 亮度调整 */
     apply_brightness();
 
+    /* 整蛊叠加层（在光标之前，覆盖页面与任务栏） */
+    prank_draw(&g_fb);
+
     /* 鼠标光标 */
     cursor_save_bg(g_mouse_x, g_mouse_y);
     cursor_draw(g_mouse_x, g_mouse_y);
@@ -216,6 +219,9 @@ static void redraw_all_fluent(void) {
     /* 亮度调整 */
     apply_brightness();
 
+    /* 整蛊叠加层（在光标之前，覆盖页面与任务栏） */
+    prank_draw(&g_fb);
+
     /* 鼠标光标 */
     cursor_save_bg(g_mouse_x, g_mouse_y);
     cursor_draw(g_mouse_x, g_mouse_y);