feat: add Resume support for CANCELLED, FAILED, and BUDGET_EXCEEDED tasks

Interrupted tasks (CANCELLED, FAILED, BUDGET_EXCEEDED) now support session
resume in addition to restart. Both buttons are shown on the task card.

- executor: extend resumablePoolStates to include CANCELLED, FAILED, BUDGET_EXCEEDED
- api: extend handleResumeTimedOutTask to accept all resumable states with
  state-specific resume messages; replace hard-coded TIMED_OUT check with a
  resumableStates map
- web: add RESUME_STATES set; render Resume + Restart buttons for interrupted
  states; TIMED_OUT keeps Resume only
- tests: 5 new Go tests (TestResumeInterrupted_*); updated task-actions.test.mjs
  with 17 tests covering dual-button behaviour

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 56 insertions, 33 deletions

diff --git a/web/test/task-actions.test.mjs b/web/test/task-actions.test.mjs
index c7d666b..a1790fa 100644
--- a/web/test/task-actions.test.mjs
+++ b/web/test/task-actions.test.mjs
@@ -6,78 +6,101 @@ import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 
 // ── Logic under test ──────────────────────────────────────────────────────────
+//
+// Interrupted states (CANCELLED, FAILED, BUDGET_EXCEEDED) get BOTH a Resume
+// button and a Restart button. TIMED_OUT gets Resume only.
+
+const RESUME_STATES   = new Set(['TIMED_OUT', 'CANCELLED', 'FAILED', 'BUDGET_EXCEEDED']);
+const RESTART_STATES  = new Set(['CANCELLED', 'FAILED', 'BUDGET_EXCEEDED']);
+
+function getCardActions(state) {
+  const actions = [];
+  if (state === 'PENDING')  return ['run'];
+  if (state === 'RUNNING')  return ['cancel'];
+  if (state === 'READY')    return ['approve'];
+  if (RESUME_STATES.has(state))  actions.push('resume');
+  if (RESTART_STATES.has(state)) actions.push('restart');
+  return actions.length ? actions : [null];
+}
 
-const RESTART_STATES = new Set(['FAILED', 'CANCELLED', 'BUDGET_EXCEEDED']);
-
-function getCardAction(state) {
-  if (state === 'PENDING') return 'run';
-  if (state === 'RUNNING') return 'cancel';
-  if (state === 'READY') return 'approve';
-  if (state === 'TIMED_OUT') return 'resume';
-  if (RESTART_STATES.has(state)) return 'restart';
-  return null;
+function getResumeEndpoint(state) {
+  return RESUME_STATES.has(state) ? '/resume' : null;
 }
 
-function getApiEndpoint(state) {
-  if (state === 'TIMED_OUT') return '/resume';
-  if (RESTART_STATES.has(state)) return '/run';
-  return null;
+function getRestartEndpoint(state) {
+  return RESTART_STATES.has(state) ? '/run' : null;
 }
 
 // ── Tests ─────────────────────────────────────────────────────────────────────
 
 describe('task card action buttons', () => {
   it('shows Run button for PENDING', () => {
-    assert.equal(getCardAction('PENDING'), 'run');
+    assert.deepEqual(getCardActions('PENDING'), ['run']);
   });
 
   it('shows Cancel button for RUNNING', () => {
-    assert.equal(getCardAction('RUNNING'), 'cancel');
+    assert.deepEqual(getCardActions('RUNNING'), ['cancel']);
   });
 
-  it('shows Restart button for FAILED', () => {
-    assert.equal(getCardAction('FAILED'), 'restart');
+  it('shows Resume AND Restart buttons for FAILED', () => {
+    assert.deepEqual(getCardActions('FAILED'), ['resume', 'restart']);
   });
 
-  it('shows Resume button for TIMED_OUT', () => {
-    assert.equal(getCardAction('TIMED_OUT'), 'resume');
+  it('shows Resume AND Restart buttons for CANCELLED', () => {
+    assert.deepEqual(getCardActions('CANCELLED'), ['resume', 'restart']);
   });
 
-  it('shows Restart button for CANCELLED', () => {
-    assert.equal(getCardAction('CANCELLED'), 'restart');
+  it('shows Resume AND Restart buttons for BUDGET_EXCEEDED', () => {
+    assert.deepEqual(getCardActions('BUDGET_EXCEEDED'), ['resume', 'restart']);
   });
 
-  it('shows Restart button for BUDGET_EXCEEDED', () => {
-    assert.equal(getCardAction('BUDGET_EXCEEDED'), 'restart');
+  it('shows Resume button only for TIMED_OUT (no restart)', () => {
+    assert.deepEqual(getCardActions('TIMED_OUT'), ['resume']);
   });
 
   it('shows approve buttons for READY', () => {
-    assert.equal(getCardAction('READY'), 'approve');
+    assert.deepEqual(getCardActions('READY'), ['approve']);
   });
 
   it('shows no button for COMPLETED', () => {
-    assert.equal(getCardAction('COMPLETED'), null);
+    assert.deepEqual(getCardActions('COMPLETED'), [null]);
   });
 
   it('shows no button for QUEUED', () => {
-    assert.equal(getCardAction('QUEUED'), null);
+    assert.deepEqual(getCardActions('QUEUED'), [null]);
   });
 });
 
 describe('task action API endpoints', () => {
   it('TIMED_OUT uses /resume endpoint', () => {
-    assert.equal(getApiEndpoint('TIMED_OUT'), '/resume');
+    assert.equal(getResumeEndpoint('TIMED_OUT'), '/resume');
+  });
+
+  it('CANCELLED uses /resume endpoint for resume', () => {
+    assert.equal(getResumeEndpoint('CANCELLED'), '/resume');
+  });
+
+  it('FAILED uses /resume endpoint for resume', () => {
+    assert.equal(getResumeEndpoint('FAILED'), '/resume');
+  });
+
+  it('BUDGET_EXCEEDED uses /resume endpoint for resume', () => {
+    assert.equal(getResumeEndpoint('BUDGET_EXCEEDED'), '/resume');
+  });
+
+  it('CANCELLED uses /run endpoint for restart', () => {
+    assert.equal(getRestartEndpoint('CANCELLED'), '/run');
   });
 
-  it('FAILED uses /run endpoint', () => {
-    assert.equal(getApiEndpoint('FAILED'), '/run');
+  it('FAILED uses /run endpoint for restart', () => {
+    assert.equal(getRestartEndpoint('FAILED'), '/run');
   });
 
-  it('CANCELLED uses /run endpoint', () => {
-    assert.equal(getApiEndpoint('CANCELLED'), '/run');
+  it('BUDGET_EXCEEDED uses /run endpoint for restart', () => {
+    assert.equal(getRestartEndpoint('BUDGET_EXCEEDED'), '/run');
   });
 
-  it('BUDGET_EXCEEDED uses /run endpoint', () => {
-    assert.equal(getApiEndpoint('BUDGET_EXCEEDED'), '/run');
+  it('TIMED_OUT has no /run restart endpoint', () => {
+    assert.equal(getRestartEndpoint('TIMED_OUT'), null);
   });
 });