Add designlang public-shell pack; tighten auth capture checks

Ran authenticated extract against coulomb.social; session metadata
matched anonymous Bubble defaults, so treat docs/design-extract as a
public shell baseline (PROVENANCE.md). Capture script now refuses to
overwrite storage-state.json with thin anonymous sessions.

docs/design-extract/tokens/tokens.flat.json

@@ -0,0 +1,127 @@
+{
+  "color": {
+    "primary": {
+      "$value": "#d08728",
+      "$type": "color"
+    },
+    "neutral-0": {
+      "$value": "#000000",
+      "$type": "color"
+    },
+    "neutral-1": {
+      "$value": "#171717",
+      "$type": "color"
+    },
+    "neutral-2": {
+      "$value": "#ffffff",
+      "$type": "color"
+    },
+    "neutral-3": {
+      "$value": "#616161",
+      "$type": "color"
+    },
+    "neutral-4": {
+      "$value": "#e5e5e5",
+      "$type": "color"
+    },
+    "background-0": {
+      "$value": "#ffffff",
+      "$type": "color"
+    },
+    "background-1": {
+      "$value": "#616161",
+      "$type": "color"
+    },
+    "text-0": {
+      "$value": "#000000",
+      "$type": "color"
+    },
+    "text-1": {
+      "$value": "#ffffff",
+      "$type": "color"
+    },
+    "text-2": {
+      "$value": "#171717",
+      "$type": "color"
+    },
+    "text-3": {
+      "$value": "#d08728",
+      "$type": "color"
+    }
+  },
+  "fontFamily": {
+    "body": {
+      "$value": "Arial",
+      "$type": "fontFamily"
+    },
+    "inter": {
+      "$value": "Inter",
+      "$type": "fontFamily"
+    }
+  },
+  "fontSize": {
+    "8": {
+      "$value": "8px",
+      "$type": "dimension"
+    },
+    "12": {
+      "$value": "12px",
+      "$type": "dimension"
+    },
+    "14": {
+      "$value": "14px",
+      "$type": "dimension"
+    },
+    "16": {
+      "$value": "16px",
+      "$type": "dimension"
+    },
+    "18": {
+      "$value": "18px",
+      "$type": "dimension"
+    },
+    "32": {
+      "$value": "32px",
+      "$type": "dimension"
+    },
+    "48": {
+      "$value": "48px",
+      "$type": "dimension"
+    },
+    "13.3333": {
+      "$value": "13.3333px",
+      "$type": "dimension"
+    }
+  },
+  "spacing": {
+    "1": {
+      "$value": "2px",
+      "$type": "dimension"
+    },
+    "16": {
+      "$value": "32px",
+      "$type": "dimension"
+    },
+    "34": {
+      "$value": "68px",
+      "$type": "dimension"
+    }
+  },
+  "borderRadius": {
+    "sm": {
+      "$value": "4px",
+      "$type": "dimension"
+    },
+    "md": {
+      "$value": "8px",
+      "$type": "dimension"
+    }
+  },
+  "shadow": {
+    "md": {
+      "$value": "rgb(97, 97, 97) 2px 2px 8px 0px",
+      "$type": "shadow"
+    }
+  },
+  "breakpoint": {}
+}