Document performance characteristics and safe usage patterns for messaging service API

[PranaviAncha]

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Description

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What

Documents the non-optimized behavior of Criteria evaluation in the messaging API.

Why

Criteria evaluation scans all ExternalView znodes when using wildcards, even for instance-only targeting. This causes severe performance degradation at scale but isn't documented, leading users to unknowingly introduce performance issues.

Tests

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Documentation (Optional)

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Code Quality

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[ngngwr]

LGTM

[ngngwr]

Please check on the java doc publishing. I do not think JAVA docs are published for any of the version

[junkaixue]

I would suggest to split the code out the documentation pr. This PR seemed to be mixing of them hard to review.