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/dsk/main.c

@@ -1327,10 +1327,11 @@ static int dsk_load_elf(u8 *data, u32 size, void **entry_out) {
         if (rela_off && rela_sz) {
             /* P0 修复: 边界检查 rela_off 和 rela_off+rela_sz 必须在 [min_vaddr, min_vaddr+isize) 内 */
             if (rela_off < min_vaddr || rela_off >= min_vaddr + isize) {
-                logl("[DSK] ELF: rela_off out of bounds, skipping reloc");
+                /* 严格错误策略：重定位表越界 = 镜像损坏，零降级 panic */
                 logh("[DSK] ELF: rela_off=", rela_off);
                 logh("[DSK] ELF: min_vaddr=", min_vaddr);
                 logh("[DSK] ELF: isize=", isize);
+                dsk_fatal("ELF-E01 RELA OUT OF BOUNDS");
                 continue;
             }
             if (rela_off + rela_sz > min_vaddr + isize) {