feat(web): Sessions, Rate-Limiting, Security-Header, Templates und eingebettete Assets

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NBHF4R9EAejDJUMdwr6C68

internal/web/templates/guides.html

@@ -0,0 +1,12 @@
+{{define "content"}}
+<h1>{{t "guides_title"}}</h1>
+<p>{{t "guides_intro"}}</p>
+{{range .Data.Guides}}
+<section class="card{{if .Suggested}} suggested{{end}}">
+  <h2>{{.Platform}}{{if .Suggested}} <span class="badge">{{t "guides_suggested"}}</span>{{end}}</h2>
+  <p class="client">{{.Client}}</p>
+  <ol>{{range .Steps}}<li>{{.}}</li>{{end}}</ol>
+</section>
+{{end}}
+<p><a href="/">{{t "back_to_overview"}}</a></p>
+{{end}}