fix: improve MCP server initialization error handling #3196 #2346 #2555 (#3243)

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  ## Summary
- Catch and log task panics during server initialization instead of
propagating JoinError
- Handle tool listing failures gracefully, allowing partial server
initialization
- Improve error resilience on macOS where init timeouts are more common

  ## Test plan
  - [x] Test MCP server initialization with timeout scenarios
  - [x] Verify graceful handling of tool listing failures
  - [x] Confirm improved error messages and logging
  - [x] Test on macOS 

 ## Fix issue  #3196 #2346 #2555
### fix before:
<img width="851" height="363" alt="image"
src="https://github.com/user-attachments/assets/e1f9c749-71fd-4873-a04f-d3fc4cbe0ae6"
/>

<img width="775" height="108" alt="image"
src="https://github.com/user-attachments/assets/4e4748bd-9dd6-42b5-b38b-8bfe9341a441"
/>

### fix improved:
<img width="966" height="528" alt="image"
src="https://github.com/user-attachments/assets/418324f3-e37a-4a3c-8bdd-934f9ff21dfb"
/>

---------

Co-authored-by: Michael Bolin <mbolin@openai.com>

codex-rs/core/src/mcp_connection_manager.rs

@@ -187,7 +187,13 @@ impl McpConnectionManager {
         let mut clients: HashMap<String, ManagedClient> = HashMap::with_capacity(join_set.len());
 
         while let Some(res) = join_set.join_next().await {
-            let (server_name, client_res) = res?; // JoinError propagation
+            let (server_name, client_res) = match res {
+                Ok((server_name, client_res)) => (server_name, client_res),
+                Err(e) => {
+                    warn!("Task panic when starting MCP server: {e:#}");
+                    continue;
+                }
+            };
 
             match client_res {
                 Ok((client, startup_timeout)) => {
@@ -205,7 +211,13 @@ impl McpConnectionManager {
             }
         }
 
-        let all_tools = list_all_tools(&clients).await?;
+        let all_tools = match list_all_tools(&clients).await {
+            Ok(tools) => tools,
+            Err(e) => {
+                warn!("Failed to list tools from some MCP servers: {e:#}");
+                Vec::new()
+            }
+        };
 
         let tools = qualify_tools(all_tools);
 
@@ -270,8 +282,19 @@ async fn list_all_tools(clients: &HashMap<String, ManagedClient>) -> Result<Vec<
     let mut aggregated: Vec<ToolInfo> = Vec::with_capacity(join_set.len());
 
     while let Some(join_res) = join_set.join_next().await {
-        let (server_name, list_result) = join_res?;
-        let list_result = list_result?;
+        let (server_name, list_result) = if let Ok(result) = join_res {
+            result
+        } else {
+            warn!("Task panic when listing tools for MCP server: {join_res:#?}");
+            continue;
+        };
+
+        let list_result = if let Ok(result) = list_result {
+            result
+        } else {
+            warn!("Failed to list tools for MCP server '{server_name}': {list_result:#?}");
+            continue;
+        };
 
         for tool in list_result.tools {
             let tool_info = ToolInfo {