feat: implement dashboard mobile responsiveness v3 overhaul (#80)

This pull request implements **Mobile Responsiveness (v3) and a High-Fidelity Overhaul** for the dashboard view layer (`/dashboard`, `/catalog`, `/my-books`, `/profile`), matching the design aesthetics of the production mobile e-reader layout.

### Key Changes
1. **Re-engineered Floating Navigation Dock Capsule:**
   - Detached bottom capsule, floating 16px off the bottom with rounded `30px` borders.
   - Glassmorphic look in dark mode (`rgba(26, 26, 30, 0.75)`) and sepia theme in light mode (`rgba(244, 241, 234, 0.9)`).
   - Removed `translateY` offset on the central "AI" action button (robot icon inside a solid green circle).
   - Used `::deep` overrides to clean up text colors and icons, preventing browser visited link purple color defaults on `NavLink` items.
   - Restored compact standalone text labels under the navigation icons.
2. **Dashboard Layout Scale Compression & Fold Optimization:**
   - Compressed profile header avatar (`40px`), welcome title font size, and status pill spacing.
   - Compressed the `concepts-linear-stack` height to `120px` with scrolling.
   - Reduced book cover heights inside `MyBooks` to `200px` on mobile viewports.
3. **Current Reading Widget & Layout Margin Safety:**
   - Localized the widget button label to `"Kontynuuj czytanie"`.
   - Used safe area clearances (`calc(1.5rem + 72px + env(safe-area-inset-bottom))`) at the bottom of pages to prevent content from being covered by the capsule.
4. **Resolved Horizontal Layout Width Blowout (Grid Fix):**
   - Discovered that `.secondary-grid` was using flex layout inherited from desktop rather than grid layout on mobile.
   - Nowrap paragraphs in the concept list stretched the flex container to over 12,000 pixels wide, breaking the entire dashboard layout width.
   - Overrode `.secondary-grid` to `display: grid !important` on mobile, properly constraining layout width and allowing nowrap concept text truncation.

### Verification
- All code changes compiled successfully under `dotnet build NexusReader.slnx --no-restore` (0 errors).
- Validated correct layouts in list view, chart view, and light/dark theme toggles on a Samsung Galaxy S20 Ultra (412x915) viewport.

---------

Co-authored-by: Marek Jasiński <jasins.marek@gmail.com>
Reviewed-on: #80
Co-authored-by: Antigravity <antigravity@google.com>
Co-committed-by: Antigravity <antigravity@google.com>

src/NexusReader.UI.Shared/Components/Organisms/CurrentReadingWidget.razor.css

@@ -194,23 +194,102 @@
     margin: 0;
 }
 
-@media (max-width: 768px) {
+@media (max-width: 767px) {
+    .current-reading-card {
+        background: #1e1e22; /* Lighter anthracite slate for depth */
+        box-shadow: 0 12px 24px rgba(0, 0, 0, 0.3); /* Ambient card shadow */
+        padding: 14px;
+        border-radius: 16px;
+        border: 1px solid var(--border);
+    }
+
     .card-layout {
         flex-direction: column;
-        align-items: center;
-        text-align: center;
-        gap: 1.5rem;
+        align-items: stretch;
+        text-align: left;
+        gap: 0.75rem;
     }
     
-    .book-title, .chapter-name {
+    .book-cover {
+        align-self: center;
+        width: 90px;
+    }
+    
+    .book-details {
+        width: 100%;
+        text-align: left;
+    }
+    
+    .book-title {
+        font-size: 1.25rem;
+        text-align: left;
         white-space: normal;
     }
+
+    .author-name {
+        text-align: left;
+        font-size: 0.8rem;
+    }
     
     .header-info, .chapter-progress {
-        align-items: center;
+        align-items: stretch;
+    }
+
+    .chapter-name {
+        white-space: normal;
+        font-size: 0.8rem;
+    }
+    
+    .chapter-progress {
+        margin: 0.5rem 0; /* Margin separator before tracking bar */
+        width: 100%;
+    }
+    
+    .progress-bar-container {
+        width: 100%;
+    }
+
+    .book-excerpt {
+        display: -webkit-box; /* Normal display to wrap synopsis */
+        overflow: hidden;
+        -webkit-line-clamp: 2;
+        -webkit-box-orient: vertical;
+        margin-bottom: 0.75rem;
+        text-align: left;
+        font-size: 0.85rem;
+    }
+    
+    .actions {
+        width: 100%;
+        margin-top: 0.25rem;
+    }
+    
+    .actions .btn-nexus.outline {
+        width: 100%;
+        justify-content: center;
+        padding: 0.75rem 1.25rem; /* Larger touch target */
+        box-sizing: border-box;
+        background: transparent !important;
+        color: var(--accent) !important;
+        border: 1px solid var(--accent) !important;
+        display: inline-flex !important;
+        align-items: center !important;
+        font-weight: 600 !important;
+    }
+
+    .actions .btn-nexus.outline:hover {
+        background: var(--accent-glow) !important;
+        color: var(--accent) !important;
+    }
+
+    .theme-light .current-reading-card {
+        background: #ffffff; /* Pure white card surface for light theme */
+        box-shadow: 0 12px 24px rgba(139, 130, 115, 0.12);
     }
 }
 
+
+
 /* ============================================================
    LIGHT THEME OVERRIDES — "Warm Paper / Soft Sepia"
    ============================================================ */