Restructure chat input layout and fix activity indicator sizing

Move send button after activity indicator in DOM order and reposition
elements via CSS. Set textarea rows to 3, increase min/max heights,
add flex-shrink to activity dot to prevent squishing, and fix
activity indicator padding and white-space handling.

styles.css

@@ -129,19 +129,10 @@
   content: '➕';
 }
 
-.ollama-input-container {
-  display: flex;
-  gap: var(--size-4-1);
-  padding: var(--size-4-2);
-  border-top: 1px solid var(--ollama-border);
-  background-color: var(--background-primary);
-  align-items: flex-end;
-}
-
 .ollama-input {
   flex: 1;
-  min-height: 2.5rem;
-  max-height: 8rem;
+  min-height: 4rem;
+  max-height: 12rem;
   padding: var(--size-4-1) var(--size-4-2);
   border-radius: var(--ollama-radius);
   border: 1px solid var(--ollama-border);
@@ -445,10 +436,10 @@
   display: none;
   align-items: center;
   gap: var(--size-4-1);
-  padding: var(--size-4-1) 0;
+  padding: var(--size-4-1) var(--size-4-1);
   font-size: var(--font-ui-small);
   color: var(--text-muted);
-  min-height: 1.5rem;
+  white-space: nowrap;
 }
 
 .ollama-activity-dot {
@@ -458,6 +449,7 @@
   border-radius: 50%;
   background-color: var(--interactive-accent);
   animation: ollama-pulse 1.2s ease-in-out infinite;
+  flex-shrink: 0;
 }
 
 .ollama-activity-text {