§H.12 steps 7-9: thread real parent VMUuid through the birth call chain

Session.parent now comes from the actual birthing VM's own
stadium_vm_id, not a hardcoded vm_uuid_hera(). Added a VMUuid parent
parameter to capsule_birth_baby() and, one level up, to
capsule_console_birth()/capsule_runcap_birth() (neither had a VM* in
their own signature, but every caller did). Updated all 6 real call
sites: BIRTH, CAPSULE-BIRTH, CONNECT-ARTEMIS, CONNECT-HERMES,
RUNCAP-TEST, PAIR-TEST (mama_forth_words.c) and the console+user birth
pair in capsule_wirebind_try_attach() (capsule_wirebind.c). Two
functions had their vm parameter marked __attribute__((unused)), now
genuinely used -- attribute removed.

Steps 8 (Session.name from capsule name) and 9 (identity defaults to
installed=0) were already satisfied by step 5's existing
session_register() call and its identity-zeroing -- confirmed by
inspection, no further code needed.

Verified 3-arch boot to ok> (amd64/aarch64/riscv64).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/starkernel/capsule/capsule_console.c

@@ -30,7 +30,7 @@ static const char CONSOLE_IDENTITY_SRC[] =
     "S\" common:messaging.4th\" EXEC\n"
     "MSG-CD-INIT\n";
 
-CapsuleRunResult capsule_console_birth(const char *console_name,
+CapsuleRunResult capsule_console_birth(const char *console_name, VMUuid parent,
                                         VMUuid *out_vm_id, void **out_vm_ctx)
 {
     if (!console_name) return CAPSULE_RUN_ERR_INVALID;
@@ -74,7 +74,7 @@ CapsuleRunResult capsule_console_birth(const char *console_name,
     dir.dir_hash      = 0;
 
     CapsuleRunResult r = capsule_birth_baby(
-        console_name, &dir, &desc, &name_entry, arena,
+        console_name, &dir, &desc, &name_entry, arena, parent,
         1 /* skip_pki_sig -- not build-time content, same rationale as RUNCAP */,
         out_vm_id, out_vm_ctx);