MINT: parameterize with full name, username, email, phone

Extends user_identity_seed_t (version 2) with fixed-size full_name/
username/email/phone fields -- plenty of unused pad space (4016 bytes)
was already there. Deliberately NOT encoded into the DER cert's Subject
field: that would mean building a real X.509 RDNSequence (OIDs for
commonName/emailAddress, PrintableString/UTF8String tagging), well past
this project's own stated "deliberately not a general ASN.1/X.509
[builder]" scope. This human-readable profile data isn't
security-relevant the way pubkey/serial are (the only two fields
CERTVERIFY/BINDSTEP actually check) -- it travels alongside the keypair
in the plain identity record instead.

capsule_mint_identity() takes full_name/username (required, validated
non-empty and within their fixed field widths) and email/phone (NULL or
empty = null, matching the schema's own nullable convention). The MINT
FORTH word's stack signature grows to 4 string pairs
( fname-c fname-u uname-c uname-u email-c email-u phone-c phone-u -- ok? ).

Verified live in QEMU: minted two real identities with real profile
data -- Zuse (full_name "Konrad Suse", username "Zuse",
zuse@pantheon.org) onto disk/zuse.img, and a regular user (full_name
"Captain Bob", username "CaptBob", capt.bob@pantheon.org) onto
disk/user1.img -- then read the raw devblock bytes back off both images
directly and confirmed every field byte-exact at its correct struct
offset. Clean 3-architecture regression boot confirms no side effects.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019ZGkimpfyh63EZyRkNbkPD

src/starkernel/capsule/mama_forth_words.c

@@ -37,10 +37,12 @@
 #ifdef __STARKERNEL__
 
 #include "platform_alloc.h"
+#include <string.h>
 #include "starkernel/capsule.h"
 #include "starkernel/capsule_birth.h"
 #include "starkernel/capsule_runcap.h"
 #include "starkernel/capsule_mint.h"
+#include "starkernel/user_identity_seed.h"
 #include "starkernel/capsule_loader.h"
 #include "starkernel/capsule_run.h"
 #include "starkernel/capsule_loader.h"
@@ -784,8 +786,44 @@ static void mama_word_vm_call(VM *vm)
  * no entropy source. Real, working code -- not the eventual Console
  * onboarding flow (§D.6), which will call this same C function.
  */
+/* Pop one ( caddr u ) string pair and copy it, NUL-terminated, into
+ * dst (capacity dst_cap). Returns 0 on success, -1 on underflow/bounds/
+ * unmapped-address failure (vm->error is set in that case). */
+static int mint_pop_string(VM *vm, char *dst, size_t dst_cap)
+{
+    if (vm->dsp < 1) { vm->error = 1; return -1; }
+    cell_t u     = vm_pop(vm);
+    cell_t caddr = vm_pop(vm);
+    if (u < 0 || (size_t)u >= dst_cap) { vm->error = 1; return -1; }
+    if (u > 0) {
+        const uint8_t *p = vm_ptr(vm, (vaddr_t)caddr);
+        if (!p) { vm->error = 1; return -1; }
+        memcpy(dst, p, (size_t)u);
+    }
+    dst[u] = '\0';
+    return 0;
+}
+
+/**
+ * @brief MINT ( fname-c fname-u uname-c uname-u email-c email-u phone-c phone-u -- ok? )
+ * Mint a fresh identity onto the currently attached USB drive, with a
+ * real human profile (FABRIC-3.md §F.20). full_name/username required
+ * and non-empty; pass a zero-length string (S" ") for email/phone to
+ * leave them null.
+ */
 static void mama_word_mint(VM *vm)
 {
+    char phone[USER_IDENTITY_PHONE_MAX];
+    char email[USER_IDENTITY_EMAIL_MAX];
+    char username[USER_IDENTITY_USERNAME_MAX];
+    char full_name[USER_IDENTITY_FULL_NAME_MAX];
+
+    /* Stack order: fname pushed first, phone last -- pop in reverse. */
+    if (mint_pop_string(vm, phone, sizeof(phone)) != 0) return;
+    if (mint_pop_string(vm, email, sizeof(email)) != 0) return;
+    if (mint_pop_string(vm, username, sizeof(username)) != 0) return;
+    if (mint_pop_string(vm, full_name, sizeof(full_name)) != 0) return;
+
     struct blkio_dev *dev = sk_repl_get_attached_blk_dev();
     if (!dev) {
         console_println("MINT: no drive attached");
@@ -793,7 +831,7 @@ static void mama_word_mint(VM *vm)
         return;
     }
 
-    MintResult r = capsule_mint_identity(dev, vm);
+    MintResult r = capsule_mint_identity(dev, vm, full_name, username, email, phone);
     switch (r) {
         case MINT_OK:
             console_println("MINT: identity minted");
@@ -814,6 +852,9 @@ static void mama_word_mint(VM *vm)
         case MINT_ERR_WRITE_FAIL:
             console_println("MINT: FAILED -- devblock write error (drive may be partially minted)");
             break;
+        case MINT_ERR_INVALID_PROFILE:
+            console_println("MINT: refused -- full_name/username missing or a field too long");
+            break;
     }
     vm_push(vm, 0);
 }