Fix code quality: cache invalidation, resource disposal, null safety, and test assertions

[niemyjski]

Summary

• Fix cache invalidation inconsistency: two scroll-based batch paths used Cache.RemoveAllAsync directly instead of InvalidateCacheAsync, bypassing subclass overrides
• Add DocumentsChanged handler check to UpdateByQuery fast-path to prevent silently missed change events when listeners are registered
• Fix PatchDocument.Load(Stream) StreamReader resource leak (add using with leaveOpen: true)
• Add null guard to Operation.Build to prevent NullReferenceException on invalid input
• Preserve inner exception in PatchDocumentConverter error handling (was losing root cause and stack trace)
• Add explicit type validation in PatchDocument.Load(JArray) for clear error messages on malformed patches
• Split Assert.NotNull(x?.Id) into separate Assert.NotNull(x) + Assert.NotNull(x.Id) across all test files (136 instances in 10 files) to prevent false-passing tests when the object itself is null

Test plan

• Core repository tests pass (47/47)
• Elasticsearch integration tests pass (requires running ES instance in CI)
• Build produces zero errors and zero new warnings

[niemyjski]

Looks good

[Copilot]

Pull request overview

This PR focuses on improving correctness and code quality across the Elasticsearch repository and JSON patch components, while also tightening test assertions to avoid false positives.

Changes:

• Fix cache invalidation and patch-by-query behavior in ElasticRepositoryBase.PatchAllAsync.
• Improve JSON Patch parsing/validation and exception preservation (PatchDocument*, Operation).
• Update many tests to split null-conditional assertions into explicit null checks.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/Foundatio.Repositories.Elasticsearch.Tests/VersionedTests.cs	Split Assert.NotNull(x?.Id) into explicit null assertions.
tests/Foundatio.Repositories.Elasticsearch.Tests/RepositoryTests.cs	Same test assertion tightening across multiple tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/ReindexTests.cs	Same test assertion tightening for reindex scenarios.
tests/Foundatio.Repositories.Elasticsearch.Tests/ReadOnlyRepositoryTests.cs	Same test assertion tightening for read-only repo tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/QueryableRepositoryTests.cs	Same test assertion tightening for queryable repo tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/QueryTests.cs	Same test assertion tightening for query behavior tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/ParentChildTests.cs	Same test assertion tightening for parent/child tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/MonthlyRepositoryTests.cs	Same test assertion tightening for monthly repository tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/IndexTests.cs	Same test assertion tightening for index maintenance/alias tests.
tests/Foundatio.Repositories.Elasticsearch.Tests/DailyRepositoryTests.cs	Same test assertion tightening for daily repository tests.
src/Foundatio.Repositories/JsonPatch/PatchDocumentConverter.cs	Preserve inner exception when wrapping invalid patch errors.
src/Foundatio.Repositories/JsonPatch/PatchDocument.cs	Fix StreamReader disposal, and add stricter JArray operation element validation.
src/Foundatio.Repositories/JsonPatch/Operation.cs	Add null guard to Operation.Build.
src/Foundatio.Repositories.Elasticsearch/Repositories/ElasticRepositoryBase.cs	Route cache invalidation through InvalidateCacheAsync and restrict UpdateByQuery fast-path when change handlers are registered.

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[Copilot]

new StreamReader(document, leaveOpen: true) is likely not a valid constructor overload for the target frameworks (net8.0/net10.0) unless an encoding parameter is also provided. This may break the build; consider using an overload that explicitly supplies the encoding and leaveOpen (or otherwise ensures the chosen overload exists across TFMs).

Suggested change

	using var reader = new StreamReader(document, leaveOpen: true);
	using var reader = new StreamReader(document, Encoding.UTF8, detectEncodingFromByteOrderMarks: true, leaveOpen: true);

[Copilot]

PatchDocument.CreateOperation can return null for an unknown/missing "op" value; Operation.Build then calls op.Read(...) and will throw a NullReferenceException. Since this method is now adding input validation, it should explicitly validate the "op" token and throw a clear ArgumentException when the operation type is unsupported.

Suggested change

	var op = PatchDocument.CreateOperation((string)jOperation["op"]);
	var opName = (string)jOperation["op"];
	if (string.IsNullOrWhiteSpace(opName))
	throw new ArgumentException("The JSON patch operation must contain a non-empty 'op' property.", nameof(jOperation));
	var op = PatchDocument.CreateOperation(opName);
	if (op is null)
	throw new ArgumentException($"Unsupported JSON patch operation type '{opName}'.", nameof(jOperation));