Add request-recording stub and request-size assertions to llworldmap_test.cpp

[Copilot]

Addresses reviewer feedback on #5560: the sendMapBlockRequest stub was a no-op, leaving the variable-size rectangle grouping logic (up to 64 regions per request) untested.

Changes

• Stub now records calls – sendMapBlockRequest populates a gMapBlockRequests vector (MapBlockRequest struct with min_x/y, max_x/y) instead of silently discarding parameters.

• New test<4> for updateRegions() – three representative cases:

  Scenario	Input	Expected
  1×1 block	updateRegions(0,0,3,3)	1 request, coords (0,0,3,3), ≤ 64 regions
  2×2 blocks	updateRegions(0,0,7,7)	1 request at the 64-region server limit
  4×4 blocks	updateRegions(0,0,15,15)	4 requests, each a 4×1-block strip (64 regions), row boundaries verified

Related Issues

• Please link to a relevant GitHub issue for additional context.
  • Bug Fix: Link to an issue that includes reproduction steps and testing guidance.
  • Feature/Enhancement: Link to an issue with a write-up, rationale, and requirements.

Issue Link: relates to #5560

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Checklist

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• All new and existing tests pass.
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• Documentation has been updated if needed.
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Additional Notes

The 4×4-block case specifically exercises the split path: the algorithm can batch at most 4 blocks (64 regions) per request, so a 16-block area must produce exactly 4 requests. Row-boundary assertions (min_y/max_y per request) confirm the strip boundaries are correct.

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