feat: Auto-detect text browsers and serve plain text CV

- Detect curl, wget, lynx, w3m, links, elinks, browsh, carbonyl
- Check User-Agent and Accept: text/plain header
- Redirect to /text endpoint automatically
- Document in SEO guide and modern techniques

internal/handlers/cv_text.go

@@ -10,6 +10,42 @@ import (
 	"text/template"
 )
 
+// Text-based browsers and CLI tools that should get plain text
+var textBrowsers = []string{
+	"curl",
+	"wget",
+	"httpie",
+	"lynx",
+	"w3m",
+	"links",
+	"elinks",
+	"browsh",
+	"carbonyl",
+	"netrik",
+	"retawq",
+	"surfraw",
+}
+
+// isTextBrowser detects if the request comes from a text-based browser or CLI tool
+func isTextBrowser(r *http.Request) bool {
+	ua := strings.ToLower(r.Header.Get("User-Agent"))
+
+	// Check for known text browsers
+	for _, browser := range textBrowsers {
+		if strings.Contains(ua, browser) {
+			return true
+		}
+	}
+
+	// Check Accept header - if client prefers text/plain
+	accept := r.Header.Get("Accept")
+	if strings.HasPrefix(accept, "text/plain") {
+		return true
+	}
+
+	return false
+}
+
 // ==============================================================================
 // PLAIN TEXT HANDLER
 // Renders CV as clean plain text for terminal/AI consumption