feat: enforce no hardcoded colors across entire CMS

Added scripts/check-admin-colors.mjs — scans all src/ files for:
- text-white, text-black (use theme text vars)
- bg-white, bg-black (use theme background/overlay vars)
- bg/text/border/ring with gray/slate/zinc/stone palette
- bg/text/border/ring with red/green/blue/etc palette

Fixed 21 violations across 11 files:
- Overlays: bg-black/* → bg-foreground/*
- Text: text-white → text-primary-foreground
- Backgrounds: bg-white/10 → bg-background/10
- Green accents: bg-green-* → bg-primary
- Red accents: bg-red-* → bg-destructive

Integrated into:
- lint-staged: runs on every *.ts/*.tsx commit
- vitest: src/lib/no-hardcoded-colors.test.ts replaces old audit test
- Allowlist: shadcn/ui primitives (button, badge, dialog) + 4 graphical files

src/components/site-header.tsx

@@ -96,7 +96,7 @@ export async function SiteHeader() {
 					) : (
 						<div className="text-center">
 							<h1
-								className="font-black tracking-tight leading-none text-white"
+								className="font-black tracking-tight leading-none text-primary-foreground"
 								style={{
 									fontFamily: "var(--font-nunito)",
 									fontSize: "clamp(2rem, 7vw, 5.5rem)",
@@ -133,8 +133,8 @@ export async function SiteHeader() {
 					}}
 				>
 					<span className="relative flex h-2 w-2 sm:h-2.5 sm:w-2.5">
-						<span className="animate-ping absolute inline-flex h-full w-full rounded-full bg-green-400 opacity-75" />
-						<span className="relative inline-flex rounded-full h-2 w-2 sm:h-2.5 sm:w-2.5 bg-green-500" />
+						<span className="animate-ping absolute inline-flex h-full w-full rounded-full bg-primary opacity-75" />
+						<span className="relative inline-flex rounded-full h-2 w-2 sm:h-2.5 sm:w-2.5 bg-primary" />
 					</span>
 					<span
 						className="text-xs sm:text-sm font-bold tracking-wide"