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

package.json

@@ -27,7 +27,8 @@
 		"test:housekeeping": "vitest run --coverage.enabled=false src/features/housekeeping src/lib/admin-theme-source-audit.test.ts src/lib/admin/authorization-contract.test.ts"
 	},
 	"lint-staged": {
-		"*.{js,ts,jsx,tsx,json}": "biome check --write --no-errors-on-unmatched"
+		"*.{js,ts,jsx,tsx,json}": "biome check --write --no-errors-on-unmatched",
+		"*.{ts,tsx}": "node scripts/check-admin-colors.mjs"
 	},
 	"dependencies": {
 		"@base-ui/react": "1.7.0",