starkernel: color the console prompt (FABRIC.md item 4.4h)

console.c's emit_prefix() now wraps [VMName] (brackets included) in
FABRIC.md 4.4's locked orange (0xFFA500), and repl.c's two "ok> "
call sites send FABRIC.md 4.4's locked cyan (0x55FFFF), both as real
SGR escape sequences through the existing font_8x16.c/vt100.c pipeline
-- 4.4b already established this needs no dependency on TTF-TEXT/4.4j.
Sent through both raw_putc() (serial) and vt100_putc() (framebuffer),
matching the existing dual-path pattern, so an ANSI-aware serial
terminal renders the same colors as the framebuffer.

Three-arch verified: amd64/aarch64/riscv64 all reach ok>, POST
Failed: 0, identical dict-hashes. Color applies correctly to any VM
name (confirmed via the [Hermes]-prefixed PARITY:BIRTH line in all
three logs, not just [Hera]). amd64 screendump confirms the rendered
colors directly.

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

src/starkernel/hal/console.c

@@ -196,9 +196,18 @@ static void raw_putc(char c) {
  * framebuffer (vt100_putc) -- mirrors console_putc()'s own serial/framebuffer
  * split so the prefix reaches both outputs, not serial only. No recursion
  * into console_putc itself (would re-trigger the line-start prefix check). */
+/* FABRIC.md 4.4: the bracketed VM name (brackets included) renders in
+ * standard web orange, 0xFFA500 -- not in the classic 16-color ANSI
+ * palette, so sent as a literal 24-bit SGR sequence rather than a palette
+ * index. Same dual serial+framebuffer send pattern as the rest of this
+ * function. */
 static void emit_prefix(void) {
     const char *p;
     int fb = fb_is_available();
+    static const char *color_on  = "\x1b[38;2;255;165;0m";
+    static const char *color_off = "\x1b[39m";
+
+    for (p = color_on; *p; p++) { raw_putc(*p); if (fb) vt100_putc(*p); }
     raw_putc('[');
     if (fb) vt100_putc('[');
     for (p = g_active_vm_name; *p; p++) {
@@ -207,6 +216,7 @@ static void emit_prefix(void) {
     }
     raw_putc(']');
     if (fb) vt100_putc(']');
+    for (p = color_off; *p; p++) { raw_putc(*p); if (fb) vt100_putc(*p); }
     raw_putc(' ');
     if (fb) vt100_putc(' ');
 }