Add dual-stream support for Frigate with optional sub-stream selection

Features:
- Optional sub-stream selection from already discovered streams
- No additional scanning required - reuse existing results
- UI: "Add Sub Stream" button to select secondary stream
- UI: "Remove Sub Stream" button to clear selection
- Smart stream routing in Frigate configs
- Go2RTC: generates _main and _sub stream names
- Frigate: detect on sub (CPU efficient), record on main (quality)
- Frigate: auto-detection of stream resolution
- Object detection: person, car, cat, dog
- Motion-based recording by default
- Live view streams configuration
- Support for any resolution: HD, 4K, 8K+
- Comprehensive documentation with examples

webui/web/css/main.css

@@ -556,12 +556,19 @@ body {
 }
 
 /* ===== CAROUSEL ===== */
-.carousel {
+.carousel-wrapper {
     position: relative;
-    overflow: hidden;
+    display: flex;
+    align-items: center;
+    gap: var(--space-4);
     margin-bottom: var(--space-4);
 }
 
+.carousel {
+    flex: 1;
+    overflow: hidden;
+}
+
 .carousel-track {
     display: flex;
     transition: transform var(--transition-slow);
@@ -621,9 +628,7 @@ body {
 }
 
 .carousel-arrow {
-    position: absolute;
-    top: 50%;
-    transform: translateY(-50%);
+    flex-shrink: 0;
     width: 48px;
     height: 48px;
     background: var(--bg-elevated);
@@ -634,7 +639,6 @@ body {
     justify-content: center;
     cursor: pointer;
     transition: all var(--transition-fast);
-    z-index: 10;
     color: var(--text-secondary);
 }
 
@@ -650,15 +654,12 @@ body {
     cursor: not-allowed;
 }
 
-.carousel-arrow-left {
-    left: -24px;
-}
-
-.carousel-arrow-right {
-    right: -24px;
-}
-
 @media (max-width: 767px) {
+    .carousel-wrapper {
+        flex-direction: column;
+        gap: var(--space-3);
+    }
+
     .carousel-arrow {
         display: none;
     }
@@ -699,14 +700,32 @@ body {
 }
 
 /* ===== SELECTED STREAM INFO ===== */
+.stream-selection-container {
+    margin-bottom: var(--space-6);
+}
+
 .selected-stream-info {
     padding: var(--space-6);
     background: var(--bg-secondary);
     border: 1px solid var(--border-color);
     border-radius: 8px;
+    margin-bottom: var(--space-4);
+    position: relative;
+}
+
+.selected-stream-info:last-child {
     margin-bottom: var(--space-6);
 }
 
+.stream-label {
+    font-size: var(--text-xs);
+    font-weight: 600;
+    color: var(--text-tertiary);
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+    margin-bottom: var(--space-3);
+}
+
 .selected-type {
     font-size: var(--text-sm);
     font-weight: 600;
@@ -723,6 +742,28 @@ body {
     word-break: break-all;
 }
 
+.sub-stream {
+    border-color: rgba(139, 92, 246, 0.3);
+}
+
+.btn-remove-sub {
+    margin-top: var(--space-4);
+    padding: var(--space-2) var(--space-4);
+    background: transparent;
+    border: 1px solid var(--error);
+    border-radius: 6px;
+    color: var(--error);
+    font-size: var(--text-sm);
+    font-weight: 500;
+    cursor: pointer;
+    transition: all var(--transition-fast);
+}
+
+.btn-remove-sub:hover {
+    background: var(--error);
+    color: white;
+}
+
 /* ===== TABS ===== */
 .tabs {
     margin-bottom: var(--space-6);
@@ -796,13 +837,32 @@ body {
 .actions {
     display: flex;
     gap: var(--space-3);
-    margin-bottom: var(--space-6);
+    margin-top: 10px;
+    margin-bottom: var(--space-4);
 }
 
 .actions .btn {
     flex: 1;
 }
 
+.secondary-actions {
+    display: flex;
+    gap: var(--space-3);
+    margin-bottom: var(--space-6);
+}
+
+.secondary-actions .btn {
+    flex: 1;
+}
+
+.secondary-actions .btn-primary {
+    flex: 1.2;
+}
+
+.secondary-actions .btn-outline {
+    flex: 0.8;
+}
+
 /* ===== TOAST ===== */
 .toast {
     position: fixed;