Add performance benchmarks, stress tests, and frontend perf tests

Go benchmarks cover item CRUD/filter/sanitization, API endpoints (stream,
item update, feed list), middleware stack (gzip, security headers, CSRF),
and crawler pipeline (feed parsing, mocked crawl). Stress tests verify
concurrent reads/writes and large dataset handling. Frontend perf tests
measure template generation, DOM insertion, and store event throughput.

New Makefile targets: bench, bench-short, stress, test-perf.

https://claude.ai/code/session_01ChDVWFDrQoFjMYHpaLGr9s

1 files changed, 90 insertions, 0 deletions

diff --git a/frontend-vanilla/src/perf/renderItems.perf.test.ts b/frontend-vanilla/src/perf/renderItems.perf.test.ts
new file mode 100644
index 0000000..3dd2ed7
--- /dev/null
+++ b/frontend-vanilla/src/perf/renderItems.perf.test.ts
@@ -0,0 +1,90 @@
+import { describe, it, expect } from 'vitest';
+import { createFeedItem } from '../components/FeedItem';
+import type { Item } from '../types';
+
+function makeItem(id: number): Item {
+    return {
+        _id: id,
+        feed_id: 1,
+        title: `Test Item ${id}`,
+        url: `https://example.com/item/${id}`,
+        description: `<p>Description for item ${id} with <b>bold</b> and <a href="https://example.com">link</a></p>`,
+        publish_date: '2024-01-01T00:00:00Z',
+        read: id % 3 === 0,
+        starred: id % 5 === 0,
+        feed_title: 'Test Feed',
+    };
+}
+
+describe('renderItems performance', () => {
+    it('createFeedItem renders 100 items under 50ms', () => {
+        const items = Array.from({ length: 100 }, (_, i) => makeItem(i));
+
+        const start = performance.now();
+        const html = items.map(item => createFeedItem(item)).join('');
+        const elapsed = performance.now() - start;
+
+        expect(html).toBeTruthy();
+        expect(html).toContain('feed-item');
+        expect(elapsed).toBeLessThan(50);
+    });
+
+    it('createFeedItem renders 500 items under 200ms', () => {
+        const items = Array.from({ length: 500 }, (_, i) => makeItem(i));
+
+        const start = performance.now();
+        const html = items.map(item => createFeedItem(item)).join('');
+        const elapsed = performance.now() - start;
+
+        expect(html).toBeTruthy();
+        expect(elapsed).toBeLessThan(200);
+    });
+
+    it('createFeedItem renders 1000 items under 100ms', () => {
+        const items = Array.from({ length: 1000 }, (_, i) => makeItem(i));
+
+        const start = performance.now();
+        const results: string[] = [];
+        for (const item of items) {
+            results.push(createFeedItem(item));
+        }
+        const elapsed = performance.now() - start;
+
+        expect(results.length).toBe(1000);
+        expect(elapsed).toBeLessThan(100);
+    });
+
+    it('DOM insertion of 100 items under 200ms', () => {
+        const items = Array.from({ length: 100 }, (_, i) => makeItem(i));
+        const html = items.map(item => createFeedItem(item)).join('');
+
+        const container = document.createElement('ul');
+        document.body.appendChild(container);
+
+        const start = performance.now();
+        container.innerHTML = html;
+        const elapsed = performance.now() - start;
+
+        expect(container.children.length).toBe(100);
+        expect(elapsed).toBeLessThan(200);
+
+        document.body.removeChild(container);
+    });
+
+    it('DOM insertion of 500 items under 500ms', () => {
+        const items = Array.from({ length: 500 }, (_, i) => makeItem(i));
+        const html = items.map(item => createFeedItem(item)).join('');
+
+        const container = document.createElement('ul');
+        document.body.appendChild(container);
+
+        const start = performance.now();
+        container.innerHTML = html;
+        const elapsed = performance.now() - start;
+
+        expect(container.children.length).toBe(500);
+        expect(elapsed).toBeLessThan(500);
+
+        document.body.removeChild(container);
+    });
+});