Quiet the POST ECW dispatch trace; three-arch clean-boot verification

vm_core.c: demote the per-word "ECW: w=... func=... 'NAME'" dispatch trace
from LOG_INFO to LOG_DEBUG. POST forces the logger to LOG_TEST for the
duration of the self-test run, and LOG_TEST includes LOG_INFO, so every
single word execution during POST was echoing this trace -- hundreds of
lines burying the actual module summaries and pass/fail tally. Still
available via --log-level=debug.

Combined with HEARTBEAT_DOE_LOG=0 (command-line Kconfig override, no
default change -- experiments/bare_metal/'s own DoE tooling still gets
HEARTBEAT_DOE_LOG=1 by default), all three architectures now boot clean:
UEFI -> POST summary -> Mama birth -> Hermes self-test -> heartbeat ->
ok>, with no [HADES][DOE] rows and no ECW flood. Verified by three-arch
QEMU boot; logs attached.

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

src/starkernel/vm/vm_core.c

@@ -771,7 +771,7 @@ void execute_colon_word(VM* vm)
         {
 #ifdef __STARKERNEL__
             g_sk_fault_word = (w->name_len > 0) ? w->name : "?";
-            log_message(LOG_INFO, "ECW: w=%p func=%p '%.*s'",
+            log_message(LOG_DEBUG, "ECW: w=%p func=%p '%.*s'",
                         (void *)(uintptr_t)w,
                         (void *)(uintptr_t)(w->func),
                         (int)w->name_len, w->name);