fix: remove static sitemap.xml to enable dynamic generation

- Delete wwwroot/sitemap.xml (static file blocking dynamic)
- Sitemap.cshtml now generates fresh URLs from DB on every request
- Includes blog posts, FAQ, announcements, contact pages
- Portal and admin pages remain excluded from robots.txt

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/TaxBaik.Web/wwwroot/sitemap.xml

@@ -1,31 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
-  <!-- 메인 홈 -->
-  <url>
-    <loc>http://178.104.200.7/taxbaik/</loc>
-    <lastmod>2026-06-29</lastmod>
-    <changefreq>daily</changefreq>
-    <priority>1.0</priority>
-  </url>
-  <!-- 고객 포털 -->
-  <url>
-    <loc>http://178.104.200.7/taxbaik/portal</loc>
-    <lastmod>2026-06-29</lastmod>
-    <changefreq>weekly</changefreq>
-    <priority>0.8</priority>
-  </url>
-  <!-- 이용약관 -->
-  <url>
-    <loc>http://178.104.200.7/taxbaik/terms</loc>
-    <lastmod>2026-06-29</lastmod>
-    <changefreq>monthly</changefreq>
-    <priority>0.3</priority>
-  </url>
-  <!-- 개인정보처리방침 -->
-  <url>
-    <loc>http://178.104.200.7/taxbaik/privacy</loc>
-    <lastmod>2026-06-29</lastmod>
-    <changefreq>monthly</changefreq>
-    <priority>0.3</priority>
-  </url>
-</urlset>