Zuse default-attach: xHCI initial-port-scan fix, ZUSEDISK wiring, mismatched-marker resync

xhci_bringup() now scans for already-connected ports at bring-up
(xhci_scan_ports_for_already_connected()), not just later hotplug events,
so a USB device present on the QEMU command line at launch is detected.
Makefile.starkernel attaches disk/zuse.img on the xhci0 bus by default in
all three arch qemu targets (ZUSEDISK=, empties for a bare boot).

capsule_mint_identity() gained a drive_known_blank param to skip a fully
redundant second homeblocks_sig_check() when the caller already confirmed
HOMEBLOCKS_SIG_BLANK itself.

Root-caused what looked like a hang after the drive attached: Artemis's
fence still carried a genesis marker from before a mid-session reformat,
while the reformatted disk/zuse.img read back BLANK -- a mismatched pair
capsule_zuse_boot_try_attach() correctly declined to act on, leaving the
boot idling at a plain ok> with nothing left to log (indistinguishable
from a hang under slow TCG). Fixed by zeroing both disk/artemis.img and
disk/zuse.img at their original sizes, giving a matched blank pair.
Verified full three-architecture acceptance: amd64 fresh genesis-mint,
aarch64/riscv64 clean reload against the same now-minted images.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KBjfeLPo71sUQ8zC7V7P5m

include/starkernel/capsule_mint.h

@@ -79,12 +79,28 @@ typedef enum {
  *                   install the cert into Hera's own VM immediately
  *                   (vm_zuse_cert_install()) -- the seed otherwise only
  *                   ever lives on the minted thumbdrive.
+ * @param drive_known_blank Pass 1 when the caller has *already* just run
+ *                   homeblocks_sig_check() on dev and confirmed
+ *                   HOMEBLOCKS_SIG_BLANK (e.g. capsule_zuse_boot_try_
+ *                   attach(), which must check sig_rc before it can even
+ *                   decide to call this) -- skips this function's own
+ *                   internal "refuse to overwrite" re-check, which
+ *                   otherwise repeats the exact same full BOT read
+ *                   sequence a second time for no reason (found live,
+ *                   FABRIC-3.md §F.25/§F.26: the redundant check was
+ *                   mistaken for a hang before the real cause -- leaked
+ *                   `tail -f` processes from repeated hard kills during
+ *                   the same debugging session -- was found). Pass 0 from
+ *                   any caller (like MINT, mama_forth_words.c) that has
+ *                   not already checked -- the safety check still applies
+ *                   there.
  * @return MINT_OK on success, an error code otherwise.
  */
 MintResult capsule_mint_identity(struct blkio_dev *dev, VM *issuer_vm,
                                   const char *full_name, const char *username,
                                   const char *email, const char *phone,
-                                  uint8_t out_pubkey[32], uint8_t out_seed[32]);
+                                  uint8_t out_pubkey[32], uint8_t out_seed[32],
+                                  int drive_known_blank);
 
 #endif /* __STARKERNEL__ */