fix: clarify upgrade indicator wording

Change "available" to "update available" so users clearly understand
a new version upgrade is pending, not just that a version exists.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: anandgupta42

packages/opencode/src/cli/cmd/tui/component/upgrade-indicator.tsx

@@ -15,7 +15,7 @@ export function UpgradeIndicator(props: { fallback?: JSX.Element }) {
         <box flexDirection="row" gap={1} flexShrink={0}>
           <text fg={theme.success}>↑</text>
           <text fg={theme.accent}>{version()}</text>
-          <text fg={theme.textMuted}>available · altimate upgrade</text>
+          <text fg={theme.textMuted}>update available · altimate upgrade</text>
         </box>
       )}
     </Show>