Polish Pattern Template UI: dialog sizing, KC editor layout, and conventions

- Fix dialog/canvas sizing: fit-content dialog follows canvas width, canvas
  max-width: 100% prevents overflow, horizontal resize supported
- Move pattern template dropdown above FPS/mode/smoothing in KC editor
- Remove emoji from pattern template dropdown options and auto-generated names
- Remove placeholder option from pattern template select, default to first
- Rename default pattern template from "Default" to "Full Screen"
- Add UI conventions to CLAUDE.md (hint pattern, select dropdown rules)

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

server/src/wled_controller/static/style.css

@@ -2708,8 +2708,9 @@ input:-webkit-autofill:focus {
 
 /* Pattern Template Visual Editor */
 .modal-content-wide {
-    max-width: 900px !important;
-    width: 95% !important;
+    width: fit-content;
+    min-width: 500px;
+    max-width: calc(100vw - 40px);
     max-height: calc(100vh - 40px);
     display: flex;
     flex-direction: column;
@@ -2717,6 +2718,7 @@ input:-webkit-autofill:focus {
 
 .modal-content-wide .modal-body {
     overflow-y: auto;
+    scrollbar-gutter: stable;
     flex: 1 1 auto;
     min-height: 0;
 }
@@ -2728,7 +2730,10 @@ input:-webkit-autofill:focus {
     background: var(--bg-color);
     border: 1px solid var(--border-color);
     margin-bottom: 12px;
-    resize: vertical;
+    resize: both;
+    width: 820px;
+    min-width: 400px;
+    max-width: 100%;
     min-height: 200px;
     height: 450px;
     max-height: calc(100vh - 400px);
@@ -2738,21 +2743,30 @@ input:-webkit-autofill:focus {
     width: 100%;
     height: 100%;
     display: block;
-    cursor: crosshair;
+    cursor: default;
 }
 
 .pattern-canvas-toolbar {
     display: flex;
-    gap: 0.5rem;
-    padding: 8px 0;
+    gap: 2px;
+    padding: 4px;
     align-items: center;
+    background: var(--bg-secondary);
+    border-radius: 6px;
+    margin-top: 4px;
 }
 
 .pattern-canvas-toolbar .btn {
     flex: 0 0 auto;
-    min-width: auto;
-    padding: 6px 12px;
-    font-size: 0.85rem;
+    min-width: 32px;
+    width: 32px;
+    height: 32px;
+    padding: 0;
+    font-size: 1rem;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    border-radius: 4px;
 }
 
 .pattern-bg-row {