feat: add serverFingerprint to MCP fetch/replace types @W-23827791@

[dgs87]

What & why

ApiCatalog.fetchMcpServer and ApiCatalog.replaceMcpServerAssets are unaware of serverFingerprint
API now returns from POST /mcp-servers/{id}/fetch and accepts on PUT /mcp-servers/{id}/assets

Without it, @salesforce/agents consumers have no way to detect that a remote MCP server's tool definitions changed between reviewing them and saving the allowlist.

Change

Added serverFingerprint?: string to two existing types in src/apiCatalogTypes.ts:

• McpServerFetchOutput — the /fetch response (producer)
• McpServerAssetReplaceInput — the PUT /assets request body (consumer)

No changes to src/apiCatalog.ts: both fetchMcpServer and replaceMcpServerAssets already pass the full body/response through the generic request() helper, so the new field flows through automatically once the types declare it. No changes to src/index.ts: both types were already re-exported.

Test plan

• Updated test/apiCatalog.test.ts: fetchMcpServer now asserts serverFingerprint is returned when present and left undefined when absent from the response;
  replaceMcpServerAssets now asserts serverFingerprint is round-tripped in the serialized request body when supplied and omitted (not sent as undefined)
  when not.
• yarn build && yarn test green (15/15), 100% statement/branch/function/line coverage on apiCatalog.ts.

this is a continuation of the work made on #325

@W-23827791@

[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @dgs87 to sign the Salesforce Inc. Contributor License Agreement.