Use kernel green for install/uninstall banner

Recolor the HYPEMAN ASCII banner from purple to the kernel brand green
(#81b300). Renames the banner color variable to KERNEL_GREEN so the
intent is explicit and keeps install.sh and uninstall.sh in sync.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: jarugupj

scripts/install.sh

@@ -27,7 +27,7 @@ SERVICE_NAME="hypeman"
 RED='\033[38;2;255;110;110m'
 GREEN='\033[38;2;92;190;83m'
 YELLOW='\033[0;33m'
-PURPLE='\033[38;2;172;134;249m'
+KERNEL_GREEN='\033[38;2;129;179;0m'
 NC='\033[0m' # No Color
 
 info() { echo -e "${GREEN}[INFO]${NC} $1"; }
@@ -793,7 +793,7 @@ fi
 # =============================================================================
 
 echo ""
-echo -e "${PURPLE}"
+echo -e "${KERNEL_GREEN}"
 cat << 'EOF'
  ██╗  ██╗  ██╗   ██╗  ██████╗   ███████╗  ███╗   ███╗   █████╗   ███╗   ██╗
  ██║  ██║  ╚██╗ ██╔╝  ██╔══██╗  ██╔════╝  ████╗ ████║  ██╔══██╗  ████╗  ██║

scripts/uninstall.sh

@@ -19,7 +19,7 @@ SERVICE_USER="hypeman"
 RED='\033[38;2;255;110;110m'
 GREEN='\033[38;2;92;190;83m'
 YELLOW='\033[0;33m'
-PURPLE='\033[38;2;172;134;249m'
+KERNEL_GREEN='\033[38;2;129;179;0m'
 NC='\033[0m' # No Color
 
 info() { echo -e "${GREEN}[INFO]${NC} $1"; }
@@ -208,7 +208,7 @@ fi
 # =============================================================================
 
 echo ""
-echo -e "${PURPLE}"
+echo -e "${KERNEL_GREEN}"
 cat << 'EOF'
  ██╗  ██╗  ██╗   ██╗  ██████╗   ███████╗  ███╗   ███╗   █████╗   ███╗   ██╗
  ██║  ██║  ╚██╗ ██╔╝  ██╔══██╗  ██╔════╝  ████╗ ████║  ██╔══██╗  ████╗  ██║