feat(types): add isMcpRegistry field to MCP protocol types (#710)

## Problem

MCP registry UI handling was using hacky type casts like `(params as
any).isRegistryActive` to determine if a server is from the registry.
This approach is not type-safe and makes the code harder to maintain and
understand.

## Solution

Add `isMcpRegistry` optional boolean field to MCP protocol types:
- `ListMcpServersParams`
- `ListMcpServersResult`
- `McpServerClickParams`
- `McpServerClickResult` (inherited from `McpServerClickParams`)

This allows proper type-safe tracking of MCP registry state throughout
the protocol communication between server and client.

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## License

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Author: ashishrp-aws

types/chat.ts

@@ -576,6 +576,7 @@ export interface ListConversationsParams {
 
 export interface ListMcpServersParams {
     filter?: Record<string, FilterValue>
+    isMcpRegistry?: boolean
 }
 
 export interface ListRulesParams {
@@ -660,6 +661,7 @@ export interface ListMcpServersResult {
     }
     list: DetailedListGroup[]
     filterOptions?: FilterOption[]
+    isMcpRegistry?: boolean
 }
 
 export type ConversationAction = 'delete' | 'export'
@@ -677,6 +679,7 @@ export interface McpServerClickParams {
     id: string
     title?: string
     optionsValues?: Record<string, string>
+    isMcpRegistry?: boolean
 }
 
 export interface McpServerClickResult extends McpServerClickParams {