tui: use standard middle dot separator for better terminal compatibility

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -1049,9 +1049,9 @@ function AssistantMessage(props: { message: AssistantMessage; parts: Part[]; las
             <text marginTop={1}>
               <span style={{ fg: local.agent.color(props.message.mode) }}>▣ </span>{" "}
               <span style={{ fg: theme.text }}>{Locale.titlecase(props.message.mode)}</span>
-              <span style={{ fg: theme.textMuted }}> ⬝ {props.message.modelID}</span>
+              <span style={{ fg: theme.textMuted }}> · {props.message.modelID}</span>
               <Show when={duration()}>
-                <span style={{ fg: theme.textMuted }}> ⬝ {Locale.duration(duration())}</span>
+                <span style={{ fg: theme.textMuted }}> · {Locale.duration(duration())}</span>
               </Show>
             </text>
           </box>