Implement the 007-add-knip feature that adds Knip unused code detection to the quality gate and as a standalone command

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -3,6 +3,7 @@
 	"packageManager": "pnpm@10.6.0",
 	"devDependencies": {
 		"@biomejs/biome": "2.0.0",
+		"knip": "^5.85.0",
 		"lefthook": "^1.11.0",
 		"typescript": "^5.8.0",
 		"vitest": "^3.0.0"
@@ -16,6 +17,7 @@
 		"typecheck": "tsc --build",
 		"test": "vitest run",
 		"test:watch": "vitest",
-		"check": "biome check . && tsc --build && vitest run"
+		"knip": "knip",
+		"check": "knip && biome check . && tsc --build && vitest run"
 	}
 }