style(agent-office): match card image to 941x1672 aspect, fill grid width

- Card image aspect-ratio 1/1 → 941/1672 (real image ratio, no crop)
- object-fit cover → contain (defensive against rounding)
- Drop card aspect-ratio so it grows from natural image+name height
- Drop grid max-width 720px so grid fills the viewport width

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/pages/agent-office/AgentOffice.css

@@ -54,14 +54,12 @@
   display: grid;
   grid-template-columns: repeat(3, 1fr);
   gap: 16px;
-  max-width: 720px;
+  width: 100%;
-  margin: 0 auto;
 }
 
 /* ===== Agent Card ===== */
 .ao-card {
   position: relative;
-  aspect-ratio: 1 / 1.15;
   background: #1e293b;
   border: 1px solid #334155;
   border-radius: 12px;
@@ -126,9 +124,8 @@
 }
 
 .ao-card-image {
-  flex: 1;
   width: 100%;
-  aspect-ratio: 1 / 1;
+  aspect-ratio: 941 / 1672;
   border-radius: 8px;
   overflow: hidden;
   background: #0f172a;
@@ -137,7 +134,7 @@
 .ao-card-image img {
   width: 100%;
   height: 100%;
-  object-fit: cover;
+  object-fit: contain;
   display: block;
 }
 .ao-card-name {