feat(theme): add SRC brand theme (Swiss red/white), keep VNClagoon default

Second builtin theme builtin-src (red #D52B1E light-first, #EF4444 dark) + SRC
mountain logo asset. VNClagoon remains the default theme. Placeholder logo.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/builtin-themes.ts

@@ -1010,6 +1010,91 @@ body[data-theme-skin="builtin-vnclagoon"] .rounded-2xl.border.bg-background\\/80
   background-image: radial-gradient(56rem 38rem at 50% -12%, rgba(0, 212, 255, 0.10), transparent 60%) !important;
 }`;
 
+// "SRC" — SRC Advisory brand. Swiss red (#D52B1E) on white, light-first, with a
+// near-black stone-grey neutral. Dark variant brightens the red (#EF4444) on a
+// warm near-black. Info stays blue so it never collides with the red accent.
+const srcCSS = `
+:root {
+  --color-border: #e7e5e4;
+  --color-input: #e7e5e4;
+  --color-ring: #d52b1e;
+  --color-background: #ffffff;
+  --color-foreground: #1c1917;
+  --color-primary: #d52b1e;
+  --color-primary-foreground: #ffffff;
+  --color-secondary: #f5f5f4;
+  --color-secondary-foreground: #1c1917;
+  --color-muted: #f5f5f4;
+  --color-muted-foreground: #78716c;
+  --color-accent: #fdecea;
+  --color-accent-foreground: #a91b12;
+  --color-destructive: #b91c1c;
+  --color-destructive-foreground: #ffffff;
+  --color-popover: #ffffff;
+  --color-popover-foreground: #1c1917;
+  --color-sidebar: #fafaf9;
+  --color-sidebar-foreground: #1c1917;
+  --color-sidebar-border: #e7e5e4;
+  --color-sidebar-accent: #f5f5f4;
+  --color-sidebar-accent-foreground: #1c1917;
+  --color-card: #ffffff;
+  --color-card-foreground: #1c1917;
+  --color-success: #16a34a;
+  --color-success-foreground: #ffffff;
+  --color-warning: #ca8a04;
+  --color-warning-foreground: #ffffff;
+  --color-info: #2563eb;
+  --color-info-foreground: #ffffff;
+  --color-selection: #fdecea;
+  --color-selection-foreground: #a91b12;
+  --color-unread: #d52b1e;
+  --color-chart-1: #d52b1e;
+  --color-chart-2: #2563eb;
+  --color-chart-3: #ca8a04;
+  --color-chart-4: #16a34a;
+  --color-chart-5: #7c3aed;
+}
+.dark {
+  --color-border: #292524;
+  --color-input: #292524;
+  --color-ring: #ef4444;
+  --color-background: #1c1917;
+  --color-foreground: #f5f5f4;
+  --color-primary: #ef4444;
+  --color-primary-foreground: #ffffff;
+  --color-secondary: #292524;
+  --color-secondary-foreground: #f5f5f4;
+  --color-muted: #292524;
+  --color-muted-foreground: #a8a29e;
+  --color-accent: #3a1e1b;
+  --color-accent-foreground: #fca5a5;
+  --color-destructive: #dc2626;
+  --color-destructive-foreground: #ffffff;
+  --color-popover: #262322;
+  --color-popover-foreground: #f5f5f4;
+  --color-sidebar: #171412;
+  --color-sidebar-foreground: #f5f5f4;
+  --color-sidebar-border: #292524;
+  --color-sidebar-accent: #292524;
+  --color-sidebar-accent-foreground: #f5f5f4;
+  --color-card: #242120;
+  --color-card-foreground: #f5f5f4;
+  --color-success: #22c55e;
+  --color-success-foreground: #ffffff;
+  --color-warning: #eab308;
+  --color-warning-foreground: #1c1917;
+  --color-info: #60a5fa;
+  --color-info-foreground: #1c1917;
+  --color-selection: rgba(213, 43, 30, 0.25);
+  --color-selection-foreground: #fca5a5;
+  --color-unread: #ef4444;
+  --color-chart-1: #ef4444;
+  --color-chart-2: #60a5fa;
+  --color-chart-3: #eab308;
+  --color-chart-4: #22c55e;
+  --color-chart-5: #a78bfa;
+}`;
+
 export const BUILTIN_THEMES: InstalledTheme[] = [
   {
     id: 'builtin-vnclagoon',
@@ -1024,6 +1109,17 @@ export const BUILTIN_THEMES: InstalledTheme[] = [
     enabled: true,
     builtIn: true,
   },
+  {
+    id: 'builtin-src',
+    name: 'SRC',
+    version: '1.0.0',
+    author: 'VNC',
+    description: 'SRC Advisory brand theme — Swiss red on white, light-first',
+    css: srcCSS,
+    variants: ['light', 'dark'],
+    enabled: true,
+    builtIn: true,
+  },
   {
     id: 'builtin-qui',
     name: 'Qui',