design: increase required minimum character count to 80 on entrepreneur onboarding step 0

vibn-frontend/_onboarding/onboarding-entrepreneur.tsx

@@ -99,12 +99,12 @@ export function EntrepIdea({ value, onChange }) {
         className="mono"
         style={{
           fontSize: 11,
-          color: "var(--fg-faint)",
+          color: value.length >= 80 ? "var(--ok)" : "var(--fg-faint)",
           letterSpacing: "0.06em",
           marginTop: -16,
         }}
       >
-        {value.length} chars · be specific where it matters
+        {value.length} / 80 chars · be specific where it matters
       </div>
     </>
   );
@@ -348,7 +348,7 @@ export function EntrepreneurPath({
         onChange={(v) => onUpdate({ idea: v })}
       />
     );
-    canNext = (data.idea || "").trim().length >= 8;
+    canNext = (data.idea || "").trim().length >= 80;
   } else if (step === 1) {
     body = (
       <EntrepAudience