feat: auto-populate suggested reps and weight in log form

Pre-fill the reps and weight inputs with progression engine suggestions
so users can log sets without manually retyping values each time.
Suggestions flow through the template chain on initial page load and
on all HTMX partial responses (log, edit, delete).

app/templates/partials/log_form.html

@@ -11,9 +11,11 @@
         <small style="white-space:nowrap; opacity:0.7;">Set {{ next_set|default(1) }}</small>
         <input type="number" name="reps" placeholder="Reps"
                min="0" max="100" required
+               {% if suggested_reps %}value="{{ suggested_reps }}"{% endif %}
                style="width:5rem; margin-bottom:0;">
         <input type="text" name="weight" placeholder="Weight (lbs)"
                required
+               {% if suggested_weight %}value="{{ suggested_weight }}"{% endif %}
                style="width:8rem; margin-bottom:0;">
         <label style="display:flex; align-items:center; gap:0.3rem; margin-bottom:0; white-space:nowrap;">
             <input type="checkbox" name="felt_easy" role="switch" style="margin-bottom:0;">