feat(05-03): Exercise research frontend integration

- Add ExerciseResearchPanel component with Get Research button, loading state, summary display, and source links
- Add ExerciseEncyclopediaPage with exercise list and integrated research panel
- Wire encyclopedia view into App.jsx navigation
- Add encyclopedia nav button to Dashboard
- Add CSS for research panel and encyclopedia search

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

frontend/src/pages/WorkoutEditPage.css

@@ -484,3 +484,169 @@
     justify-content: space-between;
   }
 }
+
+/* Encyclopedia search input */
+.encyclopedia-search {
+  width: 100%;
+  padding: 0.625rem 0.75rem;
+  border: 1px solid #ddd;
+  border-radius: 0.25rem;
+  font-size: 1rem;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+  min-height: 44px;
+  box-sizing: border-box;
+}
+
+.encyclopedia-search:focus {
+  outline: none;
+  border-color: #007bff;
+  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
+}
+
+/* Selected exercise highlight */
+.edit-exercise-card.exercise-selected {
+  border: 2px solid #007bff;
+}
+
+/* Expanded exercise detail */
+.exercise-detail-expanded {
+  border-top: 1px solid #eee;
+  padding-top: 1rem;
+  margin-top: 0.5rem;
+  display: flex;
+  flex-direction: column;
+  gap: 1rem;
+}
+
+.exercise-instructions h4 {
+  margin: 0 0 0.5rem;
+  font-size: 0.9rem;
+  color: #555;
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+}
+
+.exercise-instructions p {
+  margin: 0;
+  font-size: 0.9rem;
+  color: #444;
+  line-height: 1.6;
+}
+
+/* Research panel */
+.research-panel {
+  background: #f8f9fa;
+  border-radius: 0.375rem;
+  padding: 1rem;
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+}
+
+.research-panel-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+}
+
+.research-panel-title {
+  margin: 0;
+  font-size: 0.9rem;
+  color: #555;
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+}
+
+.research-btn {
+  padding: 0.4rem 0.9rem;
+  font-size: 0.875rem;
+  min-height: 36px;
+}
+
+.research-loading {
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+  color: #666;
+  font-size: 0.9rem;
+  padding: 0.5rem 0;
+}
+
+.research-spinner {
+  width: 18px;
+  height: 18px;
+  border: 2px solid #ddd;
+  border-top-color: #007bff;
+  border-radius: 50%;
+  animation: spin 0.8s linear infinite;
+  flex-shrink: 0;
+}
+
+.research-error {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  background: #f8d7da;
+  color: #721c24;
+  padding: 0.5rem 0.75rem;
+  border-radius: 0.25rem;
+  font-size: 0.875rem;
+}
+
+.research-results {
+  display: flex;
+  flex-direction: column;
+  gap: 0.75rem;
+}
+
+.research-summary h4,
+.research-sources h4 {
+  margin: 0 0 0.5rem;
+  font-size: 0.85rem;
+  color: #555;
+  font-weight: 600;
+}
+
+.research-summary p {
+  margin: 0;
+  font-size: 0.9rem;
+  color: #333;
+  line-height: 1.6;
+}
+
+.research-sources-list {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 0.625rem;
+}
+
+.research-source-item {
+  background: white;
+  border: 1px solid #e0e0e0;
+  border-radius: 0.25rem;
+  padding: 0.625rem 0.75rem;
+}
+
+.research-source-link {
+  color: #007bff;
+  font-size: 0.9rem;
+  font-weight: 500;
+  text-decoration: none;
+  display: block;
+  margin-bottom: 0.25rem;
+  word-break: break-word;
+}
+
+.research-source-link:hover {
+  text-decoration: underline;
+}
+
+.research-source-snippet {
+  margin: 0;
+  font-size: 0.825rem;
+  color: #555;
+  line-height: 1.5;
+}