feat: enhance dashboard with PRs, adherence, activity, progression chart, and muscle heatmap

Add 3 new stat cards (Last Workout, Personal Records, Adherence Rate),
recent activity table, progression timeline chart, and muscle group
recency heatmap to the dashboard. Remove Total Volume card.

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

app/templates/pages/dashboard.html

@@ -4,6 +4,7 @@
 
 {% block head_extra %}
 <script src="https://cdn.jsdelivr.net/npm/chart.js@4"></script>
+<script src="https://cdn.jsdelivr.net/npm/chartjs-adapter-date-fns@3"></script>
 {% endblock %}
 
 {% block content %}
@@ -28,6 +29,15 @@
     {% include "partials/volume_chart.html" %}
 </article>
 
+<!-- Recent Activity -->
+{% include "partials/recent_activity.html" %}
+
+<!-- Progression Timeline -->
+{% include "partials/progression_chart.html" %}
+
+<!-- Muscle Group Heatmap -->
+{% include "partials/muscle_heatmap.html" %}
+
 <!-- Exercise Progress Links -->
 <article>
     <header><h3>Per-Exercise Progress</h3></header>
@@ -45,5 +55,9 @@
 
 <!-- Export -->
 {% include "partials/export_form.html" %}
+
 {% endif %}
+
+<!-- Import -->
+{% include "partials/import_form.html" %}
 {% endblock %}

app/templates/partials/muscle_heatmap.html

@@ -0,0 +1,24 @@
+<article>
+    <header><h3>Muscle Group Heatmap</h3></header>
+    {% if muscle_recency %}
+    <div class="muscle-heatmap">
+        {% for mg in muscle_recency %}
+        <div class="muscle-heatmap-cell {% if mg.days_ago is none %}recency-never{% elif mg.days_ago <= 3 %}recency-fresh{% elif mg.days_ago <= 7 %}recency-ok{% elif mg.days_ago <= 14 %}recency-stale{% else %}recency-overdue{% endif %}">
+            <strong>{{ mg.muscle_group }}</strong>
+            <br>
+            {% if mg.days_ago is none %}
+            <small>Never worked</small>
+            {% elif mg.days_ago == 0 %}
+            <small>Today</small>
+            {% elif mg.days_ago == 1 %}
+            <small>1 day ago</small>
+            {% else %}
+            <small>{{ mg.days_ago }} days ago</small>
+            {% endif %}
+        </div>
+        {% endfor %}
+    </div>
+    {% else %}
+    <p>No exercises found in the library.</p>
+    {% endif %}
+</article>

app/templates/partials/progression_chart.html

@@ -0,0 +1,90 @@
+<article>
+    <header><h3>Progression Timeline</h3></header>
+    <div id="progression-container">
+        <canvas id="progression-chart" style="max-height:350px;"></canvas>
+        <div style="margin-top:0.5rem;">
+            <label for="progression-filter" style="display:inline; margin-right:0.5rem;">Exercise:</label>
+            <select id="progression-filter" style="display:inline-block; width:auto;">
+                <option value="all">All Exercises</option>
+            </select>
+        </div>
+    </div>
+    <p id="progression-empty" style="display:none;">No progression data yet.</p>
+</article>
+<script>
+(function() {
+    var timeline = {{ progression_timeline_json|safe }};
+    var exerciseData = timeline.exercises || {};
+    var names = Object.keys(exerciseData);
+
+    if (names.length === 0) {
+        document.getElementById('progression-container').style.display = 'none';
+        document.getElementById('progression-empty').style.display = 'block';
+        return;
+    }
+
+    var colors = [
+        'rgba(99, 102, 241, 1)',
+        'rgba(34, 197, 94, 1)',
+        'rgba(234, 179, 8, 1)',
+        'rgba(249, 115, 22, 1)',
+        'rgba(239, 68, 68, 1)',
+        'rgba(168, 85, 247, 1)',
+        'rgba(20, 184, 166, 1)',
+        'rgba(236, 72, 153, 1)',
+    ];
+
+    var datasets = [];
+    var filterSelect = document.getElementById('progression-filter');
+
+    names.forEach(function(name, i) {
+        var d = exerciseData[name];
+        datasets.push({
+            label: name,
+            data: d.dates.map(function(dt, j) {
+                return {x: dt, y: d.weights[j]};
+            }),
+            borderColor: colors[i % colors.length],
+            backgroundColor: colors[i % colors.length].replace('1)', '0.2)'),
+            tension: 0.3,
+            pointRadius: 3,
+            hidden: false,
+        });
+        var opt = document.createElement('option');
+        opt.value = i;
+        opt.textContent = name;
+        filterSelect.appendChild(opt);
+    });
+
+    var chart = new Chart(document.getElementById('progression-chart'), {
+        type: 'line',
+        data: {datasets: datasets},
+        options: {
+            responsive: true,
+            plugins: {
+                legend: {labels: {color: '#ccc'}},
+            },
+            scales: {
+                x: {
+                    type: 'time',
+                    time: {unit: 'week'},
+                    ticks: {color: '#ccc'},
+                },
+                y: {
+                    beginAtZero: false,
+                    title: {display: true, text: 'Weight (lbs)', color: '#ccc'},
+                    ticks: {color: '#ccc'},
+                },
+            },
+        },
+    });
+
+    filterSelect.addEventListener('change', function() {
+        var val = this.value;
+        chart.data.datasets.forEach(function(ds, i) {
+            ds.hidden = (val !== 'all' && i !== parseInt(val));
+        });
+        chart.update();
+    });
+})();
+</script>

app/templates/partials/recent_activity.html

@@ -0,0 +1,29 @@
+<article>
+    <header><h3>Recent Activity</h3></header>
+    {% if recent_activity %}
+    <div style="overflow-x:auto;">
+        <table>
+            <thead>
+                <tr>
+                    <th>Date</th>
+                    <th>Workout</th>
+                    <th>Volume (lbs)</th>
+                    <th>Sets</th>
+                </tr>
+            </thead>
+            <tbody>
+                {% for session in recent_activity %}
+                <tr>
+                    <td>{{ session.date.strftime('%b %d, %Y') }}</td>
+                    <td>{{ session.workout_day_name }}</td>
+                    <td>{{ "{:,}".format(session.total_volume) }}</td>
+                    <td>{{ session.total_sets }}</td>
+                </tr>
+                {% endfor %}
+            </tbody>
+        </table>
+    </div>
+    {% else %}
+    <p>No workout sessions logged yet.</p>
+    {% endif %}
+</article>

app/templates/partials/stats_card.html

@@ -4,12 +4,6 @@
         {{ stats.total_sessions }}
     </p>
 </article>
-<article>
-    <header><h4>Total Volume</h4></header>
-    <p style="font-size:2rem; font-weight:700;">
-        {{ "{:,}".format(stats.total_volume) }} lbs
-    </p>
-</article>
 <article>
     <header><h4>Total Sets</h4></header>
     <p style="font-size:2rem; font-weight:700;">
@@ -22,3 +16,38 @@
         {{ stats.current_streak }} week{{ "s" if stats.current_streak != 1 }}
     </p>
 </article>
+</div>
+<div class="grid">
+<article>
+    <header><h4>Last Workout</h4></header>
+    <p style="font-size:2rem; font-weight:700;">
+        {% if stats.last_workout_date %}
+        {{ stats.last_workout_date.strftime('%b %d') }}
+        {% else %}
+        Never
+        {% endif %}
+    </p>
+</article>
+<article>
+    <header><h4>Personal Records</h4></header>
+    <p style="font-size:2rem; font-weight:700;">
+        {{ personal_records|length }} PR{{ "s" if personal_records|length != 1 }}
+    </p>
+    {% if personal_records %}
+    <details>
+        <summary>View records</summary>
+        <ul style="font-size:0.85rem; margin-top:0.5rem;">
+            {% for pr in personal_records[:10] %}
+            <li>{{ pr.exercise_name }}: {{ pr.weight_display }}</li>
+            {% endfor %}
+        </ul>
+    </details>
+    {% endif %}
+</article>
+<article>
+    <header><h4>Adherence</h4></header>
+    <p style="font-size:2rem; font-weight:700;">
+        {{ adherence.rate }}%
+    </p>
+    <small>{{ adherence.completed }}/{{ adherence.expected }} sessions ({{ adherence.weeks }}wk)</small>
+</article>