Fix the dead create button on a fresh install, and make Design one surface (#89)

frontend/src/components/AppHeader.vue

@@ -64,10 +64,13 @@ router.afterEach(() => {
           <Moon v-else :size="16" />
         </button>
 
-        <!-- Design explorer. An icon rather than a sixth primary nav link: it's a
+        <!-- Design. An icon rather than a sixth primary nav link: it's a
              meta-surface like Trash and Settings, but hiding it entirely would
-             defeat the point of having somewhere the design system is visible. -->
-        <router-link to="/design" class="btn-icon" aria-label="Design" title="Design">
+             defeat the point of having somewhere the design system is visible.
+             Points at the RECORD, not the live-token view — the record is what
+             you work with; the live view is the check on it, and it's a tab
+             away. -->
+        <router-link to="/design-systems" class="btn-icon" aria-label="Design" title="Design">
           <Palette :size="16" />
         </router-link>
 
@@ -105,8 +108,7 @@ router.afterEach(() => {
       <router-link to="/rules" class="nav-link">Rulebooks</router-link>
       <router-link to="/shared" class="nav-link">Shared</router-link>
       <div class="mobile-divider"></div>
-      <router-link to="/design" class="nav-link">Design</router-link>
-      <router-link to="/design-systems" class="nav-link">Design systems</router-link>
+      <router-link to="/design-systems" class="nav-link">Design</router-link>
       <router-link to="/trash" class="nav-link">Trash</router-link>
       <router-link to="/settings" class="nav-link">Settings</router-link>
       <div class="mobile-divider"></div>

frontend/src/components/DesignTabs.vue

@@ -0,0 +1,51 @@
+<script setup lang="ts">
+/**
+ * Sub-navigation for the Design surface.
+ *
+ * There are two pages here and they are halves of ONE thing: the record that
+ * decides the styling, and what the browser is actually rendering from it. They
+ * were briefly two top-level nav entries, which put the read-only diagnostic
+ * first and buried the editable record under it — backwards, since the record
+ * is the thing you work with and the live view is the check on it.
+ *
+ * A component rather than the same markup pasted into both views: two copies of
+ * a tab bar diverge the moment a third tab appears, and that is the exact shape
+ * of duplication this whole surface exists to make visible.
+ */
+</script>
+
+<template>
+  <nav class="design-tabs" aria-label="Design views">
+    <router-link to="/design-systems" class="design-tab">Design system</router-link>
+    <router-link to="/design" class="design-tab">Live tokens</router-link>
+  </nav>
+</template>
+
+<style scoped>
+.design-tabs {
+  display: flex;
+  gap: 0.25rem;
+  margin-bottom: 1.25rem;
+  border-bottom: 1px solid var(--color-border);
+}
+
+.design-tab {
+  padding: 0.5rem 0.9rem;
+  font-size: 0.9rem;
+  color: var(--color-text-secondary);
+  text-decoration: none;
+  border-bottom: 2px solid transparent;
+  margin-bottom: -1px;
+}
+
+.design-tab:hover {
+  color: var(--color-text);
+}
+
+/* `router-link-active` rather than `-exact-active`: both routes are leaves, and
+   exact matching would drop the highlight on any future child route. */
+.design-tab.router-link-active {
+  color: var(--color-primary);
+  border-bottom-color: var(--color-primary);
+}
+</style>

frontend/src/views/DesignSystemsView.vue

@@ -42,6 +42,7 @@ import {
   type StylesheetResult,
 } from "@/api/designSystems";
 import { listRulebooks, type Rulebook } from "@/api/rulebooks";
+import DesignTabs from "@/components/DesignTabs.vue";
 import { ApiError } from "@/api/client";
 import { useToastStore } from "@/stores/toast";
 
@@ -528,14 +529,14 @@ function isColourish(value: string): boolean {
 
 <template>
   <div class="ds-view">
+    <DesignTabs />
+
     <header class="ds-header">
       <h1>Design systems</h1>
       <p class="lede">
         The design system as the record holds it. A system with a parent stores
         only what it changes, so its own list is the answer to "what does this
         one alter?" — nothing to compute.
-        <router-link to="/design">The design page</router-link> shows the other
-        side: what the browser is actually rendering right now.
       </p>
     </header>
 
@@ -547,7 +548,7 @@ function isColourish(value: string): boolean {
     </div>
 
     <!-- Empty is the ordinary state for most installs, not a broken one. -->
-    <div v-else-if="!systems.length" class="notice">
+    <div v-else-if="!systems.length && !showCreate" class="notice">
       <strong>No design systems yet.</strong>
       <p>
         A design system holds your tokens — colours, spacing, radii — as records
@@ -557,6 +558,39 @@ function isColourish(value: string): boolean {
       <button class="btn-primary" @click="showCreate = true">Create the first one</button>
     </div>
 
+    <!-- The FIRST system gets its own form, outside the list layout below.
+         `.ds-body` and the empty state are mutually exclusive branches, so a
+         form nested in the former is unreachable from the latter — which is
+         exactly the dead button this replaces. Once a system exists, the form
+         inside `.ds-body` takes over and this branch never renders. -->
+    <section v-else-if="!systems.length" class="ds-section">
+      <h2>New design system</h2>
+      <p class="section-note">
+        Nothing to inherit from yet, so this one is a family system — the house
+        style everything else departs from.
+      </p>
+      <div class="field">
+        <label class="field-label" for="first-title">Title</label>
+        <input
+          id="first-title" v-model="newTitle" class="input" type="text"
+          placeholder="FabledSword" @keyup.enter="submitCreate"
+        />
+      </div>
+      <div class="field">
+        <label class="field-label" for="first-desc">Description</label>
+        <input
+          id="first-desc" v-model="newDescription" class="input" type="text"
+          placeholder="What it covers"
+        />
+      </div>
+      <div class="row-actions">
+        <button class="btn-primary" :disabled="!newTitle.trim() || creating" @click="submitCreate">
+          {{ creating ? "Creating…" : "Create" }}
+        </button>
+        <button class="btn-ghost" @click="showCreate = false">Cancel</button>
+      </div>
+    </section>
+
     <div v-else class="ds-body">
       <!-- Systems list -->
       <aside class="ds-sidebar">

frontend/src/views/DesignView.vue

@@ -21,6 +21,7 @@
 import { computed, onMounted, ref } from "vue";
 
 import { fetchDesignExpectations } from "@/api/design";
+import DesignTabs from "@/components/DesignTabs.vue";
 import PriorityBadge from "@/components/PriorityBadge.vue";
 import StatusBadge from "@/components/StatusBadge.vue";
 import TagPill from "@/components/TagPill.vue";
@@ -101,8 +102,10 @@ const TYPE_SPECIMENS = [
 
 <template>
   <div class="design-view">
+    <DesignTabs />
+
     <header class="design-header">
-      <h1>Design</h1>
+      <h1>Live tokens</h1>
       <p class="lede">
         The system as it actually is. Token values are read from the browser at
         runtime, so this page reflects the live cascade rather than what the
@@ -110,11 +113,6 @@ const TYPE_SPECIMENS = [
         the system has no shared implementation, it is marked missing rather
         than mocked up.
       </p>
-      <p class="lede">
-        For the other half — the design system as a record you can edit, with
-        family&nbsp;&rarr;&nbsp;app inheritance — see
-        <router-link to="/design-systems">design systems</router-link>.
-      </p>
     </header>
 
     <!-- Drift: what the rulebook claims vs what the tokens do. -->