style: make editor more immersive with full-width design

- Remove border and background from full variant composer
- Increase padding for better readability
- Update toolbar padding to match content area
- Make case study panel full-width and transparent

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/lib/components/admin/ProjectForm.svelte

@@ -413,12 +413,13 @@
 	}
 
 	.panel-case-study {
-		background: white;
+		background: transparent;
 		padding: 0;
 		min-height: 80vh;
-		margin: 0 auto;
+		margin: 0;
 		display: flex;
 		flex-direction: column;
+		width: 100%;
 
 		@include breakpoint('phone') {
 			min-height: 600px;

src/lib/components/admin/composer/ComposerCore.svelte

@@ -353,7 +353,7 @@
 	.edra-editor {
 		flex: 1;
 		width: 100%;
-		padding: $unit-2x;
+		padding: $unit-4x;
 		min-height: 100px;
 		outline: none;
 		overflow-y: auto;
@@ -361,6 +361,15 @@
 		&.with-toolbar {
 			border-top: none;
 		}
+
+		// More generous padding for full variant
+		.composer--full & {
+			padding: $unit-4x $unit-6x;
+			
+			@include breakpoint('phone') {
+				padding: $unit-3x $unit-4x;
+			}
+		}
 	}
 
 	.edra-loading {
@@ -390,9 +399,7 @@
 	}
 
 	.composer--full {
-		background: $white;
+		background: transparent;
-		border: 1px solid $gray-85;
-		border-radius: $corner-radius;
 		overflow: hidden;
 	}
 </style>

src/lib/components/admin/composer/ComposerToolbar.svelte

@@ -162,8 +162,12 @@
 		display: flex;
 		align-items: center;
 		gap: 4px;
-		padding: 0 $unit-2x;
+		padding: 0 $unit-6x;
 		flex-wrap: wrap;
+		
+		@include breakpoint('phone') {
+			padding: 0 $unit-4x;
+		}
 	}
 
 	.text-style-dropdown {