Enhance visual consistency across MCP dialogs with better spacing
and appropriate icons for add/edit actions.
Changes:
- McpFormModal: Use Plus icon for "Add" button, Save icon for "Edit" button
- McpPanel: Balance spacing around server info line (py-4 for info section,
pb-4 for content area) to create equal visual weight between header and
server list
The MCP panel now has consistent vertical rhythm with 1rem spacing above
and below the server count info line.