feat: Add SEO sitemap and robots.txt generation

Implement dynamic sitemap.xml and robots.txt for search engine optimization.

## New Files

### src/routes/sitemap.xml/+server.ts
- Generate XML sitemap with all indexable pages
- Include static pages (home, matches list)
- Dynamically fetch and include recent 100 matches
- Set appropriate priority and changefreq for each URL type
- Cache response for 1 hour to reduce server load

### src/routes/robots.txt/+server.ts
- Allow all crawlers to index the site
- Point crawlers to sitemap.xml location
- Set crawl-delay of 1 second to be polite to server
- Cache response for 1 day

## Implementation Details

**Sitemap Structure:**
- Static pages: Priority 0.9-1.0, updated daily
- Match pages: Priority 0.7, updated weekly
- Fetches up to 100 most recent matches from API
- Uses match date as lastmod timestamp for accurate indexing

**SEO Benefits:**
- Helps search engines discover all match pages efficiently
- Provides crawlers with update frequency hints
- Improves indexing of dynamic content
- Reduces unnecessary crawling with robots.txt directives

The sitemap automatically stays current by fetching recent matches on each
request. The 1-hour cache balances freshness with server performance.

Note: Player profile pages not included in sitemap due to lack of bulk listing
API endpoint. Individual player pages will still be indexed via internal links.

This completes Phase 2 Feature 3 - site now properly configured for SEO.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/routes/robots.txt/+server.ts

@@ -0,0 +1,25 @@
+import type { RequestHandler } from './$types';
+
+const SITE_URL = 'https://cs2.wtf'; // Update with actual production URL
+
+/**
+ * Generate robots.txt for search engine crawlers
+ */
+export const GET: RequestHandler = async () => {
+	const robots = `User-agent: *
+Allow: /
+
+# Sitemaps
+Sitemap: ${SITE_URL}/sitemap.xml
+
+# Crawl-delay
+Crawl-delay: 1
+`;
+
+	return new Response(robots, {
+		headers: {
+			'Content-Type': 'text/plain',
+			'Cache-Control': 'public, max-age=86400' // Cache for 1 day
+		}
+	});
+};

src/routes/sitemap.xml/+server.ts

@@ -0,0 +1,65 @@
+import type { RequestHandler } from './$types';
+import { matchesAPI } from '$lib/api/matches';
+
+const SITE_URL = 'https://cs2.wtf'; // Update with actual production URL
+
+/**
+ * Generate XML sitemap for SEO
+ * Includes static pages and dynamic match pages
+ */
+export const GET: RequestHandler = async () => {
+	try {
+		// Static pages
+		const staticPages = [
+			{ url: '', priority: 1.0, changefreq: 'daily' }, // Home
+			{ url: '/matches', priority: 0.9, changefreq: 'hourly' } // Matches listing
+		];
+
+		// Fetch recent matches for dynamic URLs
+		let matchUrls: { url: string; lastmod: string }[] = [];
+		try {
+			const matchesResponse = await matchesAPI.getMatches({ limit: 100 });
+			matchUrls = matchesResponse.matches.map((match) => ({
+				url: `/match/${match.match_id}`,
+				lastmod: match.date || new Date().toISOString()
+			}));
+		} catch (error) {
+			console.error('Failed to fetch matches for sitemap:', error);
+		}
+
+		// Build XML sitemap
+		const sitemap = `<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+${staticPages
+	.map(
+		(page) => `	<url>
+		<loc>${SITE_URL}${page.url}</loc>
+		<lastmod>${new Date().toISOString()}</lastmod>
+		<changefreq>${page.changefreq}</changefreq>
+		<priority>${page.priority}</priority>
+	</url>`
+	)
+	.join('\n')}
+${matchUrls
+	.map(
+		(match) => `	<url>
+		<loc>${SITE_URL}${match.url}</loc>
+		<lastmod>${match.lastmod}</lastmod>
+		<changefreq>weekly</changefreq>
+		<priority>0.7</priority>
+	</url>`
+	)
+	.join('\n')}
+</urlset>`.trim();
+
+		return new Response(sitemap, {
+			headers: {
+				'Content-Type': 'application/xml',
+				'Cache-Control': 'public, max-age=3600' // Cache for 1 hour
+			}
+		});
+	} catch (error) {
+		console.error('Error generating sitemap:', error);
+		return new Response('Error generating sitemap', { status: 500 });
+	}
+};