docs: add missing template registration step to plan

- Add tmplPreferences variable to views.go var block
- Initialize tmplPreferences in init() function
- Add RenderPreferences function to views.go
- Fix step numbering for Task 4

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/superpowers/plans/2026-03-22-brave-search-frontend-redesign.md

@@ -982,10 +982,35 @@ Append to `kafka.css`:
 }
 ```
 
-- [ ] **Step 3: Commit**
+- [ ] **Step 3: Register preferences template in views.go**
+
+Add `tmplPreferences` variable and initialize it in `init()`. Also add `RenderPreferences` function:
+
+```go
+// In views.go, add to var block:
+var (
+    tmplFull        *template.Template
+    tmplIndex       *template.Template
+    tmplFragment    *template.Template
+    tmplPreferences *template.Template
+)
+
+// In init(), after existing template parsing, add:
+tmplPreferences = template.Must(template.New("").Funcs(funcMap).ParseFS(tmplFS,
+    "base.html", "preferences.html",
+))
+
+// Add RenderPreferences function:
+func RenderPreferences(w http.ResponseWriter, sourceURL string) error {
+    w.Header().Set("Content-Type", "text/html; charset=utf-8")
+    return tmplPreferences.ExecuteTemplate(w, "base", PageData{ShowHeader: true, SourceURL: sourceURL})
+}
+```
+
+- [ ] **Step 4: Commit**
 
 ```bash
-git add internal/views/templates/preferences.html internal/views/static/css/kafka.css
+git add internal/views/templates/preferences.html internal/views/static/css/kafka.css internal/views/views.go
 git commit -m "feat(frontend): add preferences page template and styles"
 ```