Speed up /mcp inventory listing (#16831)

Addresses #16244

This was a performance regression introduced when we moved the TUI on
top of the app server API.

Problem: `/mcp` rebuilt a full MCP inventory through
`mcpServerStatus/list`, including resources and resource templates that
made the TUI wait on slow inventory probes.

Solution: add a lightweight `detail` mode to `mcpServerStatus/list`,
have `/mcp` request tools-and-auth only, and cover the fast path with
app-server and TUI tests.

Testing: Confirmed slow (multi-second) response prior to change and
immediate response after change.

I considered two options:
1. Change the existing `mcpServerStatus/list` API to accept an optional
"details" parameter so callers can request only a subset of the
information.
2. Add a separate `mcpServer/list` API that returns only the servers,
tools, and auth but omits the resources.

I chose option 1, but option 2 is also a reasonable approach.

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -1949,6 +1949,18 @@ pub struct ListMcpServerStatusParams {
     /// Optional page size; defaults to a server-defined value.
     #[ts(optional = nullable)]
     pub limit: Option<u32>,
+    /// Controls how much MCP inventory data to fetch for each server.
+    /// Defaults to `Full` when omitted.
+    #[ts(optional = nullable)]
+    pub detail: Option<McpServerStatusDetail>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(rename_all = "camelCase", export_to = "v2/")]
+pub enum McpServerStatusDetail {
+    Full,
+    ToolsAndAuthOnly,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]