🎯 Changes

Several tests used loose matchers that pass as long as something is present, without checking the actual value. Where the thrown/forwarded value is deterministic (thrown by the test itself, or a fixed source message), the assertions are tightened to the exact value.

• lit-query — infinite-and-options, mutation-controller — toBeInstanceOf(Error) → toEqual(new Error('<message>')). Each error is thrown by the test's own queryFn/mutationFn (next-page-failed, negative-not-allowed, reset-target), and the sibling rejects.toThrow('<message>') already checks the same message, so the error object is now checked to match it too.
• query-core — timeoutManager — the second argument of the provider-switch warning was expect.anything() (any non-null value); it now asserts the exact { previous, provider } payload the source passes.
• query-devtools — Explorer — the clipboard copy failure logs console.error('Failed to copy: ', err); expect.any(Error) → the exact new Error('denied') the test's writeText mock rejects with.
• vue-query — useQueryClient — bare toThrow() → toThrow('<message>') for the two guards (No 'queryClient' found ... and vue-query hooks can only be used inside setup() ...), which the source throws unconditionally.

✅ Checklist

• I have followed the steps in the Contributing guide.
• I have tested this code locally.

🚀 Release Impact

• This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

• Tests
  • Improved test coverage by verifying exact error values and messages across pagination, mutations, timeout handling, clipboard failures, and Vue query-client usage.
  • Added more precise validation for timeout-provider warnings and missing query-client guidance.