UI polish: hover lift, skeleton loaders, empty states, badge contrast, transitions

Card & row interactions:
- NoteCard, TaskCard, ProjectCard: translateY(-2px) lift on hover + extended transitions
- Kanban task cards (ProjectView), note rows: same lift treatment
- Task rows in flat/grouped list: soft indigo bg tint on hover
- Chat conversation items: left-border accent + bg tint on hover (was border-only)
- HomeView project mini-cards: translateY(-2px) lift on hover

Global feedback:
- Buttons: scale(0.97) on :active press (theme.css, :not(:disabled) scoped)
- TagPill: color → primary + indigo bg tint on hover
- StatusBadge: increased opacity 15% → 22% + stronger text color for readability

Loading & empty states:
- TasksListView: shimmer skeleton loader (6 rows) + rich empty state with CTA
- ProjectListView: shimmer skeleton cards (4) + rich empty state with CTA
- HomeView: section-empty messages for overdue/high-priority/notes sections
- ProjectView kanban columns: dashed-border styled empty state

Transitions & graph:
- WorkspaceView panels: panel-fade opacity transition on show/hide (v-if inner wrap)
- GraphView D3 nodes: grow to r*1.3 + bold label on mouseover (150ms transition)
- Milestone action buttons: base opacity 0 → 0.35 for discoverability

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

frontend/src/views/ProjectView.vue

@@ -1031,10 +1031,11 @@ function formatDate(dateStr?: string | null): string {
   text-decoration: none;
   color: var(--color-text);
   font-size: 0.875rem;
-  transition: border-color 0.15s;
+  transition: border-color 0.15s, transform 0.18s ease;
 }
 .task-card:hover {
   border-color: var(--color-primary);
+  transform: translateY(-2px);
 }
 .task-card-done .task-title {
   text-decoration: line-through;
@@ -1069,11 +1070,13 @@ function formatDate(dateStr?: string | null): string {
   color: var(--color-text-muted);
 }
 .col-empty {
-  font-size: 0.8rem;
-  color: var(--color-text-muted);
   text-align: center;
-  padding: 0.5rem 0;
-  margin: 0;
+  padding: 1.5rem 0.5rem;
+  color: var(--color-text-muted);
+  font-size: 0.82rem;
+  border: 1px dashed var(--color-border);
+  border-radius: var(--radius-sm);
+  margin-top: 0.5rem;
 }
 
 /* Notes list */
@@ -1093,10 +1096,11 @@ function formatDate(dateStr?: string | null): string {
   text-decoration: none;
   color: var(--color-text);
   font-size: 0.9rem;
-  transition: border-color 0.15s;
+  transition: border-color 0.15s, transform 0.15s ease;
 }
 .note-row:hover {
   border-color: var(--color-primary);
+  transform: translateY(-1px);
 }
 .note-title {
   font-weight: 500;
@@ -1193,7 +1197,7 @@ function formatDate(dateStr?: string | null): string {
   display: flex;
   gap: 0.15rem;
   margin-left: 0.25rem;
-  opacity: 0;
+  opacity: 0.35;
   transition: opacity 0.15s;
 }
 .milestone-header:hover .ms-actions {