refactor: Integrate PreferencesMiddleware and update handlers

Complete middleware integration with comprehensive testing:

1. Middleware Integration
   - Added PreferencesMiddleware to middleware chain in routes
   - Order: Recovery → Logger → SecurityHeaders → Preferences → Mux
   - Reads all preference cookies once per request
   - Stores in context for handlers to access

2. Handler Updates
   - cv_pages.go: Home handler uses middleware.GetPreferences()
   - cv_htmx.go: All toggle handlers use middleware preferences
   - Eliminated manual cookie reading in handlers
   - Migration logic handled entirely by middleware

3. Comprehensive Middleware Tests
   - Created preferences_test.go with 10+ test functions
   - Tests: default values, migrations, cookie setting, context access
   - Verified: extended→long, true→show, false→hide migrations
   - All tests passing

Benefits:
- Performance: Cookies read once per request (not multiple times)
- Consistency: All handlers get same preference values
- Maintainability: Migration logic centralized in middleware
- Testability: Easy to mock preferences via context

Testing:
- All unit tests pass (handlers + middleware)
- Build succeeds
- No breaking changes

internal/handlers/cv_htmx.go

@@ -2,6 +2,8 @@ package handlers
 
 import (
 	"net/http"
+
+	"github.com/juanatsap/cv-site/internal/middleware"
 )
 
 // ==============================================================================
@@ -17,13 +19,9 @@ func (h *CVHandler) ToggleLength(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Get current state
-	currentLength := getPreferenceCookie(r, "cv-length", "short")
-
-	// Migrate old value if needed
-	if currentLength == "extended" {
-		currentLength = "long"
-	}
+	// Get current preferences from context (set by middleware, already migrated)
+	prefs := middleware.GetPreferences(r)
+	currentLength := prefs.CVLength
 
 	// Toggle state
 	newLength := "long"
@@ -32,12 +30,12 @@ func (h *CVHandler) ToggleLength(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Save new state
-	setPreferenceCookie(w, "cv-length", newLength)
+	middleware.SetPreferenceCookie(w, "cv-length", newLength)
 
-	// Get language
+	// Get language from query or use current preference
 	lang := r.URL.Query().Get("lang")
 	if lang == "" {
-		lang = getPreferenceCookie(r, "cv-language", "en")
+		lang = prefs.CVLanguage
 	}
 
 	// Prepare template data with length state
@@ -72,16 +70,9 @@ func (h *CVHandler) ToggleIcons(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Get current state
-	currentIcons := getPreferenceCookie(r, "cv-icons", "show")
-
-	// Migrate old values if needed
-	switch currentIcons {
-	case "true":
-		currentIcons = "show"
-	case "false":
-		currentIcons = "hide"
-	}
+	// Get current preferences from context (set by middleware, already migrated)
+	prefs := middleware.GetPreferences(r)
+	currentIcons := prefs.CVIcons
 
 	// Toggle state
 	newIcons := "hide"
@@ -90,12 +81,12 @@ func (h *CVHandler) ToggleIcons(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Save new state
-	setPreferenceCookie(w, "cv-icons", newIcons)
+	middleware.SetPreferenceCookie(w, "cv-icons", newIcons)
 
-	// Get language
+	// Get language from query or use current preference
 	lang := r.URL.Query().Get("lang")
 	if lang == "" {
-		lang = getPreferenceCookie(r, "cv-language", "en")
+		lang = prefs.CVLanguage
 	}
 
 	// Prepare template data with logo state
@@ -135,7 +126,7 @@ func (h *CVHandler) SwitchLanguage(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Save language preference
-	setPreferenceCookie(w, "cv-language", lang)
+	middleware.SetPreferenceCookie(w, "cv-language", lang)
 
 	// Prepare template data
 	data, err := h.prepareTemplateData(lang)
@@ -144,19 +135,17 @@ func (h *CVHandler) SwitchLanguage(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Preserve current length and logo preferences
-	cvLength := getPreferenceCookie(r, "cv-length", "short")
-	cvIcons := getPreferenceCookie(r, "cv-icons", "show")
-	cvTheme := getPreferenceCookie(r, "cv-theme", "default")
+	// Get current preferences from context (set by middleware)
+	prefs := middleware.GetPreferences(r)
 
 	// Add preferences to data
-	if cvLength == "long" {
+	if prefs.CVLength == "long" {
 		data["CVLengthClass"] = "cv-long"
 	} else {
 		data["CVLengthClass"] = "cv-short"
 	}
-	data["ShowIcons"] = (cvIcons == "show")
-	data["ThemeClean"] = (cvTheme == "clean")
+	data["ShowIcons"] = (prefs.CVIcons == "show")
+	data["ThemeClean"] = (prefs.CVTheme == "clean")
 
 	// Render language-switch template with out-of-band swaps
 	tmpl, err := h.templates.Render("language-switch.html")
@@ -179,8 +168,9 @@ func (h *CVHandler) ToggleTheme(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Get current state
-	currentTheme := getPreferenceCookie(r, "cv-theme", "default")
+	// Get current preferences from context (set by middleware)
+	prefs := middleware.GetPreferences(r)
+	currentTheme := prefs.CVTheme
 
 	// Toggle state
 	newTheme := "clean"
@@ -189,12 +179,12 @@ func (h *CVHandler) ToggleTheme(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Save new state
-	setPreferenceCookie(w, "cv-theme", newTheme)
+	middleware.SetPreferenceCookie(w, "cv-theme", newTheme)
 
-	// Get language
+	// Get language from query or use current preference
 	lang := r.URL.Query().Get("lang")
 	if lang == "" {
-		lang = getPreferenceCookie(r, "cv-language", "en")
+		lang = prefs.CVLanguage
 	}
 
 	// Prepare template data with theme state

internal/handlers/cv_pages.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/juanatsap/cv-site/internal/middleware"
 	"github.com/juanatsap/cv-site/internal/pdf"
 )
 
@@ -43,26 +44,13 @@ func (h *CVHandler) Home(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Get user preferences from context (set by middleware)
-	// Note: Middleware should be enabled in routes for this to work
-	// For now, fall back to direct cookie reading for backward compatibility
-	cvLength := getPreferenceCookie(r, "cv-length", "short")
-	cvIcons := getPreferenceCookie(r, "cv-icons", "show")
-	cvTheme := getPreferenceCookie(r, "cv-theme", "default")
+	// Get user preferences from context (set by PreferencesMiddleware)
+	prefs := middleware.GetPreferences(r)
 
-	// Migrate old preference values to new ones (one-time auto-migration)
-	if cvLength == "extended" {
-		cvLength = "long"
-		setPreferenceCookie(w, "cv-length", "long")
-	}
-	switch cvIcons {
-	case "true":
-		cvIcons = "show"
-		setPreferenceCookie(w, "cv-icons", "show")
-	case "false":
-		cvIcons = "hide"
-		setPreferenceCookie(w, "cv-icons", "hide")
-	}
+	// Use preferences from context (already migrated by middleware)
+	cvLength := prefs.CVLength
+	cvIcons := prefs.CVIcons
+	cvTheme := prefs.CVTheme
 
 	// Add preference-specific fields to template data
 	cvLengthClass := "cv-short"