vMCP backend queries do not follow pagination cursors (silent truncation past 1000 tools)

Context

While writing regression tests for the mcp-go → go-sdk migration (#5742), a pagination regression was discovered.

Finding

pkg/vmcp/client/client.go queryTools (around line 700) does a single ListTools with ListToolsRequest{} — no cursor loop. The go-sdk paginates tools/list at DefaultPageSize=1000, so backends with >1000 tools are silently truncated.

The same issue applies to queryResources and queryPrompts.

Impact: vMCP servers aggregating backends with >1000 tools will silently drop tools beyond the first page. Non-cursor-following clients see an incomplete tool set.

Regression test coverage

• TestRegression_Over1000Tools_CompleteSetReceived in test/integration/vmcp/pagination_regression_test.go — skipped test with t.Skip("vMCP does not follow pagination cursors; see gap-analysis V1 / follow-up issue"). Serves as a regression anchor for when cursor-following is implemented.

MCP spec reference

MCP 2025-11-25 §"Pagination": tools/list supports cursor; servers MAY paginate. Clients must follow nextCursor.

Acceptance criteria

• queryTools, queryResources, and queryPrompts should follow pagination cursors until exhausted
• The skipped test should be un-skipped and pass
• A backend exposing >1000 tools should return the complete set through vMCP

Start in pkg/vmcp/client/client.go at queryTools, queryResources, and queryPrompts, then read the pagination regression anchor in test/integration/vmcp/pagination_regression_test.go. Use TestRegression_Over1000Tools_CompleteSetReceived to verify that cursor-based results are complete, unskip it, and confirm the test passes for backends with more than 1000 tools.