Extract authenticated coulomb.social design language via designlang

Session probe lands on /vw_pages (Research). Use main designlang extract
with --cookie-file — pack ignores auth. 39 artifacts under
docs/design-extract; tolerate designlang late summary crash when cores exist.

docs/design-extract/coulomb-social-visual-dna.json

@@ -0,0 +1,53 @@
+{
+  "materialLanguage": {
+    "label": "flat",
+    "confidence": 0,
+    "signals": [],
+    "metrics": {
+      "saturation": 0.101,
+      "shadowProfile": "soft",
+      "avgShadowBlur": 0,
+      "maxShadowBlur": 0,
+      "insetShadows": 0,
+      "avgRadius": 11.8,
+      "maxRadius": 20,
+      "hasPill": false,
+      "hasBackdropBlur": false,
+      "gradientCount": 0
+    },
+    "alternates": []
+  },
+  "imageryStyle": {
+    "label": "mixed",
+    "confidence": 0,
+    "counts": {
+      "total": 29,
+      "svg": 0,
+      "icon": 1,
+      "hero": 0,
+      "screenshot": 0,
+      "photoLike": 0
+    },
+    "dominantAspect": "square-ish",
+    "radiusProfile": "soft",
+    "alternates": [],
+    "signals": []
+  },
+  "backgroundPatterns": {
+    "labels": [
+      "plain"
+    ],
+    "counts": {
+      "noise": 0,
+      "dotGrid": 0,
+      "lineGrid": 0,
+      "meshCount": 0,
+      "svgPattern": 0
+    },
+    "gradientTotals": {
+      "radial": 0,
+      "linear": 0
+    },
+    "samples": []
+  }
+}