♻️ refactor: On-demand MCP connections: remove proactive reconnect, default to available (#11839)

* feat: Implement reconnection staggering and backoff jitter for MCP connections

- Enhanced the reconnection logic in OAuthReconnectionManager to stagger reconnection attempts for multiple servers, reducing the risk of connection storms.
- Introduced a backoff delay with random jitter in MCPConnection to improve reconnection behavior during network issues.
- Updated the ConnectionsRepository to handle multiple server connections concurrently with a defined concurrency limit.

Added tests to ensure the new reconnection strategy works as intended.

* refactor: Update MCP server query configuration for improved data freshness

- Reduced stale time from 5 minutes to 30 seconds to ensure quicker updates on server initialization.
- Enabled refetching on window focus and mount to enhance data accuracy during user interactions.

* ♻️  refactor: On-demand MCP connections; remove proactive reconnection, default to available

  - Remove reconnectServers() from refresh controller (connection storm root cause)
  - Stop gating server selection on connection status; add to selection immediately
  - Render agent panel tools from DB cache, not live connection status
  - Proceed to cached tools on init failure (only gate on OAuth)
  - Remove unused batchToggleServers()
  - Reduce useMCPServersQuery staleTime from 5min to 30s, enable refetchOnMount/WindowFocus

* refactor: Optimize MCP tool initialization and server connection logic

- Adjusted tool initialization to only occur if no cached tools are available, improving efficiency.
- Updated comments for clarity on server connection and tool fetching processes.
- Removed unnecessary connection status checks during server selection to streamline the user experience.

client/src/hooks/MCP/useMCPServerManager.ts

@@ -433,33 +433,6 @@ export function useMCPServerManager({
     [startupConfig?.interface?.mcpServers?.placeholder, localize],
   );
 
-  const batchToggleServers = useCallback(
-    (serverNames: string[]) => {
-      const connectedServers: string[] = [];
-      const disconnectedServers: string[] = [];
-
-      serverNames.forEach((serverName) => {
-        if (isInitializing(serverName)) {
-          return;
-        }
-
-        const serverStatus = connectionStatus?.[serverName];
-        if (serverStatus?.connectionState === 'connected') {
-          connectedServers.push(serverName);
-        } else {
-          disconnectedServers.push(serverName);
-        }
-      });
-
-      setMCPValues(connectedServers);
-
-      disconnectedServers.forEach((serverName) => {
-        initializeServer(serverName);
-      });
-    },
-    [connectionStatus, setMCPValues, initializeServer, isInitializing],
-  );
-
   const toggleServerSelection = useCallback(
     (serverName: string) => {
       if (isInitializing(serverName)) {
@@ -473,15 +446,10 @@ export function useMCPServerManager({
         const filteredValues = currentValues.filter((name) => name !== serverName);
         setMCPValues(filteredValues);
       } else {
-        const serverStatus = connectionStatus?.[serverName];
-        if (serverStatus?.connectionState === 'connected') {
-          setMCPValues([...currentValues, serverName]);
-        } else {
-          initializeServer(serverName);
-        }
+        setMCPValues([...currentValues, serverName]);
       }
     },
-    [mcpValues, setMCPValues, connectionStatus, initializeServer, isInitializing],
+    [mcpValues, setMCPValues, isInitializing],
   );
 
   const handleConfigSave = useCallback(
@@ -677,7 +645,6 @@ export function useMCPServerManager({
     isPinned,
     setIsPinned,
     placeholderText,
-    batchToggleServers,
     toggleServerSelection,
     localize,