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, 124 insertions, 0 deletions

diff --git a/frontend-vanilla/src/perf/store.perf.test.ts b/frontend-vanilla/src/perf/store.perf.test.ts
new file mode 100644
index 0000000..734e132
--- /dev/null
+++ b/frontend-vanilla/src/perf/store.perf.test.ts
@@ -0,0 +1,124 @@
+import { describe, it, expect } from 'vitest';
+import { Store } from '../store';
+import type { Item, Feed, Category } from '../types';
+
+function makeItem(id: number): Item {
+    return {
+        _id: id,
+        feed_id: 1,
+        title: `Test Item ${id}`,
+        url: `https://example.com/item/${id}`,
+        description: `Description for item ${id}`,
+        publish_date: '2024-01-01T00:00:00Z',
+        read: false,
+        starred: false,
+        feed_title: 'Test Feed',
+    };
+}
+
+function makeFeed(id: number): Feed {
+    return {
+        _id: id,
+        url: `https://example.com/feed/${id}`,
+        web_url: `https://example.com/${id}`,
+        title: `Feed ${id}`,
+        category: `cat-${id % 5}`,
+    };
+}
+
+describe('store performance', () => {
+    it('setItems with 500 items + event dispatch under 10ms', () => {
+        const store = new Store();
+        const items = Array.from({ length: 500 }, (_, i) => makeItem(i));
+
+        let eventFired = false;
+        store.on('items-updated', () => { eventFired = true; });
+
+        const start = performance.now();
+        store.setItems(items);
+        const elapsed = performance.now() - start;
+
+        expect(store.items.length).toBe(500);
+        expect(eventFired).toBe(true);
+        expect(elapsed).toBeLessThan(10);
+    });
+
+    it('setItems append 500 items to existing 500 under 10ms', () => {
+        const store = new Store();
+        const initial = Array.from({ length: 500 }, (_, i) => makeItem(i));
+        const more = Array.from({ length: 500 }, (_, i) => makeItem(i + 500));
+
+        store.setItems(initial);
+
+        const start = performance.now();
+        store.setItems(more, true);
+        const elapsed = performance.now() - start;
+
+        expect(store.items.length).toBe(1000);
+        expect(elapsed).toBeLessThan(10);
+    });
+
+    it('setFeeds with 200 feeds under 5ms', () => {
+        const store = new Store();
+        const feeds = Array.from({ length: 200 }, (_, i) => makeFeed(i));
+
+        let eventFired = false;
+        store.on('feeds-updated', () => { eventFired = true; });
+
+        const start = performance.now();
+        store.setFeeds(feeds);
+        const elapsed = performance.now() - start;
+
+        expect(store.feeds.length).toBe(200);
+        expect(eventFired).toBe(true);
+        expect(elapsed).toBeLessThan(5);
+    });
+
+    it('rapid filter changes (100 toggles) under 50ms', () => {
+        const store = new Store();
+        const filters: Array<'unread' | 'all' | 'starred'> = ['unread', 'all', 'starred'];
+        let eventCount = 0;
+        store.on('filter-updated', () => { eventCount++; });
+
+        const start = performance.now();
+        for (let i = 0; i < 100; i++) {
+            store.setFilter(filters[i % 3]);
+        }
+        const elapsed = performance.now() - start;
+
+        expect(eventCount).toBeGreaterThan(0);
+        expect(elapsed).toBeLessThan(50);
+    });
+
+    it('rapid search query changes (100 updates) under 50ms', () => {
+        const store = new Store();
+        let eventCount = 0;
+        store.on('search-updated', () => { eventCount++; });
+
+        const start = performance.now();
+        for (let i = 0; i < 100; i++) {
+            store.setSearchQuery(`query-${i}`);
+        }
+        const elapsed = performance.now() - start;
+
+        expect(eventCount).toBe(100);
+        expect(elapsed).toBeLessThan(50);
+    });
+
+    it('multiple listeners (50) on items-updated under 10ms', () => {
+        const store = new Store();
+        const items = Array.from({ length: 100 }, (_, i) => makeItem(i));
+        let totalCalls = 0;
+
+        for (let i = 0; i < 50; i++) {
+            store.on('items-updated', () => { totalCalls++; });
+        }
+
+        const start = performance.now();
+        store.setItems(items);
+        const elapsed = performance.now() - start;
+
+        expect(totalCalls).toBe(50);
+        expect(elapsed).toBeLessThan(10);
+    });
+});