Use full-width layout for the web shell and topbar.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/app.css

@@ -69,9 +69,10 @@ code {
 }
 
 .app-shell {
-  max-width: 1200px;
-  margin: 0 auto;
-  padding: 0 1.25rem 1.25rem;
+  width: 100%;
+  min-height: 100vh;
+  margin: 0;
+  padding: 0;
 }
 .topbar {
   position: sticky;
@@ -81,7 +82,8 @@ code {
   gap: 1rem;
   align-items: center;
   justify-content: space-between;
-  margin: 0 -1.25rem 1.25rem;
+  width: 100%;
+  margin: 0 0 1.25rem;
   padding: 0.85rem 1.25rem;
   border-bottom: 1px solid var(--line);
   background: color-mix(in srgb, var(--bg) 92%, transparent);
@@ -102,6 +104,7 @@ code {
   display: grid;
   gap: 1rem;
   min-width: 0;
+  padding: 0 1.25rem 1.25rem;
 }
 .app-body.with-sidebar {
   grid-template-columns: 220px minmax(0, 1fr);