[mcp] Support MCP Apps part 2 - Add meta to mcp tool call result. (#16465)

- [x] Add meta to mcp tool call result.

codex-rs/app-server/src/bespoke_event_handling.rs

@@ -2843,6 +2843,7 @@ async fn construct_mcp_tool_call_end_notification(
             Some(McpToolCallResult {
                 content: value.content.clone(),
                 structured_content: value.structured_content.clone(),
+                meta: value.meta.clone(),
             }),
             None,
         ),
@@ -4233,7 +4234,9 @@ mod tests {
             content: content.clone(),
             is_error: Some(false),
             structured_content: None,
-            meta: None,
+            meta: Some(serde_json::json!({
+                "ui/resourceUri": "ui://widget/list-resources.html"
+            })),
         };
 
         let end_event = McpToolCallEndEvent {
@@ -4268,6 +4271,9 @@ mod tests {
                 result: Some(McpToolCallResult {
                     content,
                     structured_content: None,
+                    meta: Some(serde_json::json!({
+                        "ui/resourceUri": "ui://widget/list-resources.html"
+                    })),
                 }),
                 error: None,
                 duration_ms: Some(0),