fix: stream session updates live

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/renderer/sessionWorkspace.test.ts

@@ -0,0 +1,130 @@
+import { describe, expect, test } from 'bun:test';
+
+import { applySessionEventWorkspace } from '@renderer/lib/sessionWorkspace';
+import type { SessionEventRecord } from '@shared/domain/event';
+import type { WorkspaceState } from '@shared/domain/workspace';
+
+describe('session workspace helpers', () => {
+  function createWorkspace(): WorkspaceState {
+    return {
+      projects: [],
+      patterns: [],
+      sessions: [
+        {
+          id: 'session-1',
+          projectId: 'project-1',
+          patternId: 'pattern-1',
+          title: 'Session',
+          createdAt: '2026-03-23T00:00:00.000Z',
+          updatedAt: '2026-03-23T00:00:00.000Z',
+          status: 'idle',
+          messages: [],
+        },
+      ],
+      selectedSessionId: 'session-1',
+      lastUpdatedAt: '2026-03-23T00:00:00.000Z',
+    };
+  }
+
+  test('applies message deltas by creating and appending assistant messages', () => {
+    const created = applySessionEventWorkspace(createWorkspace(), {
+      sessionId: 'session-1',
+      kind: 'message-delta',
+      occurredAt: '2026-03-23T00:00:01.000Z',
+      messageId: 'assistant-1',
+      authorName: 'Architect',
+      contentDelta: 'Hello',
+    } satisfies SessionEventRecord);
+
+    expect(created?.sessions[0].messages).toEqual([
+      {
+        id: 'assistant-1',
+        role: 'assistant',
+        authorName: 'Architect',
+        content: 'Hello',
+        createdAt: '2026-03-23T00:00:01.000Z',
+        pending: true,
+      },
+    ]);
+
+    const appended = applySessionEventWorkspace(created, {
+      sessionId: 'session-1',
+      kind: 'message-delta',
+      occurredAt: '2026-03-23T00:00:02.000Z',
+      messageId: 'assistant-1',
+      authorName: 'Architect',
+      contentDelta: ' world',
+    } satisfies SessionEventRecord);
+
+    expect(appended?.sessions[0].messages[0]).toMatchObject({
+      authorName: 'Architect',
+      content: 'Hello world',
+      pending: true,
+    });
+  });
+
+  test('marks streamed messages complete when the session event arrives', () => {
+    const workspace = applySessionEventWorkspace(createWorkspace(), {
+      sessionId: 'session-1',
+      kind: 'message-delta',
+      occurredAt: '2026-03-23T00:00:01.000Z',
+      messageId: 'assistant-1',
+      authorName: 'Implementer',
+      contentDelta: 'Done',
+    } satisfies SessionEventRecord);
+
+    const completed = applySessionEventWorkspace(workspace, {
+      sessionId: 'session-1',
+      kind: 'message-complete',
+      occurredAt: '2026-03-23T00:00:02.000Z',
+      messageId: 'assistant-1',
+      authorName: 'Implementer',
+    } satisfies SessionEventRecord);
+
+    expect(completed?.sessions[0].messages[0]).toMatchObject({
+      authorName: 'Implementer',
+      content: 'Done',
+      pending: false,
+    });
+  });
+
+  test('updates session status and error state from session events', () => {
+    const running = applySessionEventWorkspace(createWorkspace(), {
+      sessionId: 'session-1',
+      kind: 'status',
+      occurredAt: '2026-03-23T00:00:01.000Z',
+      status: 'running',
+    } satisfies SessionEventRecord);
+
+    expect(running?.sessions[0]).toMatchObject({
+      status: 'running',
+      lastError: undefined,
+    });
+
+    const failed = applySessionEventWorkspace(running, {
+      sessionId: 'session-1',
+      kind: 'error',
+      occurredAt: '2026-03-23T00:00:02.000Z',
+      error: 'Boom',
+    } satisfies SessionEventRecord);
+
+    expect(failed?.sessions[0]).toMatchObject({
+      status: 'error',
+      lastError: 'Boom',
+    });
+  });
+
+  test('ignores events for unknown sessions', () => {
+    const workspace = createWorkspace();
+    expect(
+      applySessionEventWorkspace(workspace, {
+        sessionId: 'missing',
+        kind: 'message-delta',
+        occurredAt: '2026-03-23T00:00:01.000Z',
+        messageId: 'assistant-1',
+        authorName: 'Architect',
+        contentDelta: 'Hello',
+      } satisfies SessionEventRecord),
+    ).toBe(workspace);
+  });
+});