feat: add smart "Workout Now" recommendation to workout picker

Auto-recommends the next workout in the 4-day cycle based on the
user's last completed session (one with logged sets). Redesigns
the /workouts page with highlighted recommendation card and
renames the back button to "Change Workout".

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

app/templates/pages/workout_day.html

@@ -27,5 +27,5 @@
     {% endfor %}
 </section>
 
-<a href="/workouts" role="button" class="outline">Back to All Days</a>
+<a href="/workouts" role="button" class="outline">Change Workout</a>
 {% endblock %}

app/templates/pages/workout_days.html

@@ -1,20 +1,36 @@
 {% extends "base.html" %}
 
-{% block title %}Workout Days — SneakySwole{% endblock %}
+{% block title %}Workout Now — SneakySwole{% endblock %}
 
 {% block content %}
-<h1>Workout Days</h1>
+<h1>Workout Now</h1>
+
+<p>
+    {% if last_workout_name %}
+    Last workout: <strong>{{ last_workout_name }}</strong> on {{ last_workout_date.strftime('%b %-d') }}
+    {% else %}
+    No workouts yet — start with Push!
+    {% endif %}
+</p>
 
 <div class="grid">
     {% for day in days %}
     <article>
         <header>
             <h3>Day {{ day.day_number }}: {{ day.name }}</h3>
+            {% if day.id == recommended_day_id %}
+            <mark>Recommended Next</mark>
+            {% endif %}
         </header>
         <p>{{ day.description }}</p>
         <footer>
+            {% if day.id == recommended_day_id %}
             <a href="/workouts/{{ day.name|lower|replace(' ', '-') }}"
-               role="button">View Workout</a>
+               role="button">Start Workout</a>
+            {% else %}
+            <a href="/workouts/{{ day.name|lower|replace(' ', '-') }}"
+               role="button" class="outline">Start Workout</a>
+            {% endif %}
         </footer>
     </article>
     {% endfor %}