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/DKM/ehci/ehci.c

@@ -1098,10 +1098,12 @@ int driver_init(const struct dkm_kernel_api *api,
             dkm_delay_ms(20);
         }
     }
-    dkm_delay_ms(100);  /* 端口稳定 */
+    dkm_delay_ms(1500);  /* 控制器复位后 U 盘重新连接 */
 
-    /* 扫描端口，枚举 MSC */
+    /* 扫描端口，枚举 MSC。第一遍没有就再等一次。 */
     g_msc.ready = 0;
+    for (int pass = 0; pass < 2 && !g_msc.ready; pass++) {
+    if (pass == 1) dkm_delay_ms(1500);
     for (u32 p = 0; p < g_nports; p++) {
         u32 po = g_caplen + EHCI_OP_PORTSC + p * EHCI_PORT_STRIDE;
         u32 ps = mmio_read32(po);
@@ -1138,6 +1140,7 @@ int driver_init(const struct dkm_kernel_api *api,
         log_hex("[ehci] MSC device block_size=", blk);
         break;
     }
+    }
 
     /* 注册 block provider */
     if (g_msc.ready && api->block && api->block->register_device) {