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>

knip.json

@@ -0,0 +1,10 @@
+{
+	"$schema": "https://unpkg.com/knip@5/schema.json",
+	"workspaces": {
+		".": {
+			"entry": ["scripts/*.mjs"]
+		},
+		"packages/*": {},
+		"apps/*": {}
+	}
+}