feat(plan): Start planning button on project view

frontend/src/views/ProjectView.vue

@@ -3,6 +3,7 @@ import { ref, computed, onMounted, watch } from "vue";
 import { useRoute, useRouter } from "vue-router";
 import { apiGet, apiPatch, apiDelete, apiPost } from "@/api/client";
 import { useToastStore } from "@/stores/toast";
+import { useTasksStore } from "@/stores/tasks";
 import { relativeTime } from "@/composables/useRelativeTime";
 import ShareDialog from "@/components/ShareDialog.vue";
 import ProjectRulesTab from "@/components/rules/ProjectRulesTab.vue";
@@ -62,9 +63,28 @@ interface NoteItem {
 const route = useRoute();
 const router = useRouter();
 const toast = useToastStore();
+const tasksStore = useTasksStore();
 
 const project = ref<Project | null>(null);
 const loading = ref(false);
+
+const showStartPlanning = ref(false);
+const planTitle = ref("");
+const planningBusy = ref(false);
+
+async function confirmStartPlanning() {
+  const title = planTitle.value.trim();
+  if (!title || !project.value) return;
+  planningBusy.value = true;
+  try {
+    const result = await tasksStore.startPlanning(project.value.id, title);
+    planTitle.value = "";
+    showStartPlanning.value = false;
+    router.push(`/tasks/${result.task.id}`);
+  } finally {
+    planningBusy.value = false;
+  }
+}
 const saving = ref(false);
 const error = ref<string | null>(null);
 
@@ -340,12 +360,35 @@ async function confirmDelete() {
     <div class="page-header">
       <router-link to="/projects" class="btn-back">← Projects</router-link>
       <div class="page-header-actions">
-        <router-link v-if="project" :to="`/workspace/${project.id}`" class="btn-workspace">
+        <template v-if="showStartPlanning">
+          <input
+            v-model="planTitle"
+            class="plan-title-input"
+            placeholder="Plan title…"
+            @keyup.enter="confirmStartPlanning"
+          />
+          <button
+            class="btn-workspace"
+            :disabled="!planTitle.trim() || planningBusy"
+            @click="confirmStartPlanning"
+          >
+            Create plan
+          </button>
+          <button class="btn-share" @click="showStartPlanning = false; planTitle = ''">Cancel</button>
+        </template>
+        <button
+          v-else-if="project"
+          class="btn-workspace"
+          @click="showStartPlanning = true"
+        >
+          Start planning
+        </button>
+        <router-link v-if="project && !showStartPlanning" :to="`/workspace/${project.id}`" class="btn-workspace">
           <LayoutGrid :size="16" />
           Workspace
         </router-link>
-        <button v-if="project" class="btn-share" @click="showShare = true">Share</button>
+        <button v-if="project && !showStartPlanning" class="btn-share" @click="showShare = true">Share</button>
-        <button v-if="project" class="btn-danger-outline" @click="showDeleteConfirm = true">Delete</button>
+        <button v-if="project && !showStartPlanning" class="btn-danger-outline" @click="showDeleteConfirm = true">Delete</button>
       </div>
     </div>
 
@@ -685,6 +728,15 @@ async function confirmDelete() {
   margin-bottom: 1.5rem;
 }
 .page-header-actions { display: flex; gap: 0.5rem; align-items: center; }
+.plan-title-input {
+  background: var(--color-bg, #111113);
+  color: inherit;
+  border: 1px solid var(--color-border, #2a2a2e);
+  border-radius: 6px;
+  padding: 0.4rem 0.6rem;
+  font: inherit;
+  min-width: 200px;
+}
 
 .btn-back {
   display: inline-flex;