feat: SKEL skeleton instrumentation - designed-but-unimplemented paths panic

- hypercall.c: 5 Phase 1.3 stubs -> HCALL-E01..E05 panic (no NOSYS return)
- drr_stub.c: snapshot alloc fail -> DRR-E01; new skeletons DRR-E02 root key
  seal, DRR-E03 task kill crypto erase, DRR-E04/E05 segment/system rollback,
  DRR-E06/E07 driver recovery ops dispatch
- sched.c: enable fail -> SCH-E02 panic (no silent demo skip)
- dkm/kernel_api.c: D1 hot-unload DKM-E01, D2 bare code loader DKM-E02,
  SIPI AP wake DKM-E03 skeletons
- virtio_net tx/rx stubs -> VNET-E01/E02; ath9k tx stub -> ATH-E01;
  xhci port reset -> XHC-E01; nvme MSI/MSI-X fail -> NVME-E01..E03 (no
  silent polling downgrade); e1000 MAC fallback -> E1K-E01
- pe_shim unimpl API -> PE-E01; PE ordinal import -> PE-E02
- kernel/main.c: lib sync / vscode install fail -> LNX-E01/E02
- NEW brand/brand.c (E1 boot anim BRAND-E01, E2 time egg BRAND-E02) and
  pkg/pkg.c (pacman skeleton PKG-E01..03), wired into UTSM MAKEFILE
- Deliberate design-internal fallbacks kept and documented (VMX skip,
  bzImage skip, KDE fallback, boot-module fallback, apic->PIC route)

CODE/DKM/nvme/nvme.c

@@ -920,13 +920,17 @@ static int nvme_msix_program(const struct dkm_kernel_api *api,
      * 页属性 PCD|PWT (UC), MSI-X 表访问不要求 cache 一致性操作。 */
     volatile u32 *tbl = (volatile u32 *)api->mm_map_mmio(tbl_phys, 4096);
     if (!tbl) {
-        g_log->warn("[nvme] MSI-X: table MMIO map failed; polling");
+        /* 严格错误策略插桩：MSI-X 表映射失败不允许静默转轮询（NVME-E01） */
+        g_log->error("[nvme] MSI-X: table MMIO map failed");
+        g_log->panic("NVME-E01 MSIX TABLE MAP FAILED");
         return 0;
     }
 
     int vector = api->irq_vector_alloc();
     if (vector < 0 || vector > 255) {
-        g_log->warn("[nvme] MSI-X: vector alloc failed; polling");
+        /* 严格错误策略插桩：向量分配失败不允许静默转轮询（NVME-E02） */
+        g_log->error("[nvme] MSI-X: vector alloc failed");
+        g_log->panic("NVME-E02 VECTOR ALLOC FAILED");
         return 0;
     }
     log_dec("[nvme] MSI-X vector=", (u64)vector);
@@ -958,7 +962,10 @@ static int nvme_msix_program(const struct dkm_kernel_api *api,
     log_hex("[nvme] MSI-X readback entry vctl=", rb_vc);
     if (!(rb_ctl & 0x8000u) || rb_a0 != addr || rb_a1 != 0 ||
         (rb_d & 0xffu) != ((u32)vector & 0xffu) || (rb_vc & 1u)) {
-        g_log->warn("[nvme] MSI-X: readback mismatch; rolling back");
+        /* 严格错误策略插桩：MSI-X 编程回读不符 = 硬件/虚拟机拒绝消息中断，
+         * 不允许静默回滚转轮询（NVME-E03）。 */
+        g_log->error("[nvme] MSI-X: readback mismatch");
+        g_log->panic("NVME-E03 MSIX READBACK MISMATCH");
         u32 rb = dkm_pci_read(bus, dev, func, (u8)cap);
         rb = (rb & 0x0000ffffu) | (msg_ctl << 16);      /* 恢复原 msg_ctl */
         dkm_pci_write(bus, dev, func, (u8)cap, rb);