feat: show New Task button on all tabs

Removed the switchTab() logic that hid btn-new-task on non-tasks tabs.
The button lives in the global header so no structural changes were needed.
Added new-task-button.test.mjs to contract-test the always-visible behavior.

2 files changed, 27 insertions, 4 deletions

diff --git a/web/app.js b/web/app.js
index 3121f28..187795f 100644
--- a/web/app.js
+++ b/web/app.js
@@ -278,6 +278,9 @@ export function filterActiveTasks(tasks) {
   return tasks.filter(t => _PANEL_ACTIVE_STATES.has(t.state));
 }
 
+// The New Task button is always visible regardless of active tab.
+export function newTaskButtonShouldShowOnTab(_tab) { return true; }
+
 export function filterTasksByTab(tasks, tab) {
   if (tab === 'active')      return tasks.filter(t => ACTIVE_STATES.has(t.state));
   if (tab === 'interrupted') return tasks.filter(t => INTERRUPTED_STATES.has(t.state));
@@ -2198,10 +2201,6 @@ function switchTab(name) {
     }
   });
 
-  // Show/hide the header New Task button (only relevant on tasks tab)
-  document.getElementById('btn-new-task').style.display =
-    name === 'tasks' ? '' : 'none';
-
   if (name === 'running') {
     fetchTasks().then(renderRunningView).catch(() => {
       const currentEl = document.querySelector('.running-current');
diff --git a/web/test/new-task-button.test.mjs b/web/test/new-task-button.test.mjs
new file mode 100644
index 0000000..45a3548
--- /dev/null
+++ b/web/test/new-task-button.test.mjs
@@ -0,0 +1,24 @@
+// new-task-button.test.mjs — visibility contract for the New Task button
+//
+// The New Task button lives in the global header and must be visible on all tabs.
+// Run with: node --test web/test/new-task-button.test.mjs
+
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import { newTaskButtonShouldShowOnTab } from '../app.js';
+
+const ALL_TABS = ['tasks', 'active', 'running', 'stats'];
+
+describe('new task button visibility', () => {
+  for (const tab of ALL_TABS) {
+    it(`is visible on "${tab}" tab`, () => {
+      assert.equal(newTaskButtonShouldShowOnTab(tab), true, `expected button to be visible on tab "${tab}"`);
+    });
+  }
+
+  it('is visible on any unknown future tab', () => {
+    assert.equal(newTaskButtonShouldShowOnTab('help'), true);
+    assert.equal(newTaskButtonShouldShowOnTab('templates'), true);
+    assert.equal(newTaskButtonShouldShowOnTab(''), true);
+  });
+});