Fix agent output summary for pipeline steps (#812)

* Changes from fix/agent-output-summary-for-pipeline-steps

* feat: Optimize pipeline summary extraction and fix regex vulnerability

* fix: Use fallback summary for pipeline steps when extraction fails

* fix: Strip follow-up session scaffold from pipeline step fallback summaries

apps/server/tests/unit/ui/log-parser-mixed-format.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, it } from 'vitest';
+import {
+  parseAllPhaseSummaries,
+  parsePhaseSummaries,
+  extractPhaseSummary,
+  extractImplementationSummary,
+  isAccumulatedSummary,
+} from '../../../../ui/src/lib/log-parser.ts';
+
+describe('log-parser mixed summary format compatibility', () => {
+  const mixedSummary = [
+    'Implemented core auth flow and API wiring.',
+    '',
+    '---',
+    '',
+    '### Code Review',
+    '',
+    'Addressed lint warnings and improved error handling.',
+    '',
+    '---',
+    '',
+    '### Testing',
+    '',
+    'All tests passing.',
+  ].join('\n');
+
+  it('treats leading headerless section as Implementation phase', () => {
+    const phases = parsePhaseSummaries(mixedSummary);
+
+    expect(phases.get('implementation')).toBe('Implemented core auth flow and API wiring.');
+    expect(phases.get('code review')).toBe('Addressed lint warnings and improved error handling.');
+    expect(phases.get('testing')).toBe('All tests passing.');
+  });
+
+  it('returns implementation summary from mixed format', () => {
+    expect(extractImplementationSummary(mixedSummary)).toBe(
+      'Implemented core auth flow and API wiring.'
+    );
+  });
+
+  it('includes Implementation as the first parsed phase entry', () => {
+    const entries = parseAllPhaseSummaries(mixedSummary);
+
+    expect(entries[0]).toMatchObject({
+      phaseName: 'Implementation',
+      content: 'Implemented core auth flow and API wiring.',
+    });
+    expect(entries.map((entry) => entry.phaseName)).toEqual([
+      'Implementation',
+      'Code Review',
+      'Testing',
+    ]);
+  });
+
+  it('extracts specific phase summaries from mixed format', () => {
+    expect(extractPhaseSummary(mixedSummary, 'Implementation')).toBe(
+      'Implemented core auth flow and API wiring.'
+    );
+    expect(extractPhaseSummary(mixedSummary, 'Code Review')).toBe(
+      'Addressed lint warnings and improved error handling.'
+    );
+    expect(extractPhaseSummary(mixedSummary, 'Testing')).toBe('All tests passing.');
+  });
+
+  it('treats mixed format as accumulated summary', () => {
+    expect(isAccumulatedSummary(mixedSummary)).toBe(true);
+  });
+});