banner: more detailed ornate skeleton key

The v0.4.1 box-drawing key was minimalist — round bow, line shaft,
small bit. Replaced with a more detailed ornate skeleton-key
silhouette in the classic ASCII-art-of-keys tradition:

  - Round bow with internal "hole" rendered via stylized 8/b/d/'
    pattern (suggests the decorative loop you'd grip)
  - Long shaft running right across the banner
  - Bit at the end with a staircase notch pattern (the iconic
    "key-tooth" descent showing the wards that engage the lock)

Same height as the previous banner. SKELETONKEY block letters
below unchanged.

Bump 0.4.1 → 0.4.2.

skeletonkey.c

@@ -28,17 +28,20 @@
 #include <string.h>
 #include <unistd.h>
 
-#define SKELETONKEY_VERSION "0.4.1"
+#define SKELETONKEY_VERSION "0.4.2"
 
 static const char BANNER[] =
 "\n"
-"      ╭───╮\n"
-"     ╱     ╲\n"
-"    │   ●   │════════════════════════════════════════════════════════╗\n"
-"     ╲     ╱                                                      ╔══╩══╗\n"
-"      ╰───╯                                                       ║   ╔═╝\n"
-"                                                                  ║   ║\n"
-"                                                                  ╚═══╝\n"
+"       ,d8888b,\n"
+"      d88'  `88b\n"
+"     d88' ,db, `88b\n"
+"     88  d8''8b  88===========================================,\n"
+"     88  88  88  88                                            `=,\n"
+"     88  `8bd8'  88                                              \"Yb,\n"
+"     `8b  `\"\"'  d8'                                                Yb\n"
+"      Y8,      ,8P                                              ,d8'\n"
+"       `Y8888P''                                              ,d8P'\n"
+"                                                            d8P\"\n"
 "\n"
 " ███████╗██╗  ██╗███████╗██╗     ███████╗████████╗ ██████╗ ███╗   ██╗██╗  ██╗███████╗██╗   ██╗\n"
 " ██╔════╝██║ ██╔╝██╔════╝██║     ██╔════╝╚══██╔══╝██╔═══██╗████╗  ██║██║ ██╔╝██╔════╝╚██╗ ██╔╝\n"