Address PR #1221 code review feedback

- Fix getCapabilityEntries to iterate fixed key sets so unsupported
  capabilities render red X (was only showing present/supported ones)
- Merge duplicate @mantine/core import in ViewHeader
- Move ConnectionState from ServerCard to core/mcp/types.ts
- Narrow onConnectionModeChange to "proxy" | "direct" instead of string

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/mcp/types.ts

@@ -60,6 +60,16 @@ export type ConnectionStatus =
   | "connected"
   | "error";
 
+/**
+ * Snapshot of a server's connection state, used by dumb components
+ * that display status, retry count, and error details.
+ */
+export interface ConnectionState {
+  status: ConnectionStatus;
+  retryCount?: number;
+  error?: { message: string; details?: string };
+}
+
 export interface StderrLogEntry {
   timestamp: Date;
   message: string;