Draft: CheckBatch: Add module for batched configure-time checks

Add the CheckBatch module, which answers many try_compile-class configure checks with a handful of compiler invocations instead of one nested configure+build per check. Queries are declared in a batch and resolved either by a single, always-successful "survey" compile that encodes answers as magic strings in the object file (nothing runs, so it is cross-compile safe) or by a parallel "probe" build in which compile/link failure is the answer.

Results are published as the conventional INTERNAL cache variables with matching helpstrings, so they compose with existing check-result caches and with code that tests the usual HAVE_* variables. When the compiler or generator cannot support batching, every query transparently falls back to the classic Check* modules with identical results.

Document the module in cmake-modules(7), add a release note, and add a RunCMake test suite covering every query kind, the CHECKBATCH_DISABLE fallback, the CHECKBATCH_VERIFY cross-check, and argument-handling errors.

Relates to #27945