fix: Re-enable SA1615 return value documentation rule (#14)

[daviburg]

Summary

Re-enables StyleCop SA1615 (return value documentation) as a warning to prevent regression, now that all public methods have <returns>\ tags from prior PRs. Also promotes SA1623 and SA1629 to warning (zero violations exist).

Changes

File	Change
.editorconfig\	SA1615 \
one\ → \warning, SA1623 \
one\ → \warning, SA1629 \
one\ → \warning\
.github/copilot-instructions.md\	Updated rule: require <returns>\ tags on public methods
.gitattributes\	New — enforces LF line endings (* text=auto eol=lf) matching .editorconfig\
18 .cs\ files	45 doc comment fixes (38 SA1615 + 6 SA1623 + 1 SA1629)

Verification

• \dotnet build --nologo\ — 0 warnings
• \dotnet test --nologo\ — 233 passed, 15 skipped, 0 failed
• \dotnet format --verify-no-changes\ — clean

Closes #14

[Copilot]

Pull request overview

This PR re-enables several StyleCop XML documentation rules (notably SA1615) and updates repository guidance/configuration so return value documentation is consistently present and enforced going forward.

Changes:

• Re-enabled SA1615/SA1623/SA1629 in .editorconfig as warning.
• Updated Copilot contributor guidance to require <returns> tags on public APIs.
• Added/adjusted XML doc comments across server code and introduced .gitattributes to enforce LF endings.

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Server/Services/Connections/DirectClientConnection.cs	Updates property XML docs to SA1623-compliant “Gets or sets …” wording.
Server/Services/Connections/ConnectionsConfig.cs	Updates property XML docs to SA1623-compliant wording.
Server/Services/CompilationService.cs	Adds <returns> documentation to multiple methods to satisfy SA1615.
Server/Services/CodeLens/CodeLensConfig.cs	Updates property XML docs to SA1623-compliant wording.
Server/Services/Api/ApiServiceConfig.cs	Updates read-only property summary to “Gets …” wording.
Server/SdkIndex.cs	Adds <returns> documentation for several public/internal APIs (incl. async factory).
Server/LogSanitizer.cs	Adds <returns> documentation for SanitizeUrl.
Server/Handlers/HoverHandler/SdkDynamicOperationsDiscovery.cs	Adds <returns> documentation for config fallback lookup.
Server/Handlers/HoverHandler/HoverHandlerTypes.cs	Adjusts XML doc punctuation to satisfy SA1629.
Server/Handlers/CompletionHandler/CompletionHandler.cs	Adds <returns> documentation for helper methods returning nullable strings.
Server/Handlers/CodeActionHandler/SchemaToClassGenerator.cs	Adds <returns> documentation for generator helpers.
Server/Handlers/CodeActionHandler/GenerateDynamicSchemaCommandHandler.cs	Adds <returns> documentation for source-update helper.
Server/Handlers/CodeActionHandler/DynamicSchemaCodeActionHandler.cs	Adds <returns> documentation for detection/name generation helpers.
Server/Handlers/CodeActionHandler/DynamicSchemaCache.cs	Adds <returns> documentation for cache build/scan methods.
Server/ExceptionExtensions.cs	Adds <returns> documentation for IsFatal.
Server/DynamicValuesHelper.cs	Adds <returns> documentation for helper methods.
Server/Diagnostics/Validators/ValidatorHelpers.cs	Adds <returns> documentation for validator helper utilities.
Server/Diagnostics/LevenshteinDistance.cs	Adds <returns> documentation for Compute.
Server/Diagnostics/IDiagnosticValidator.cs	Adds <returns> documentation for the validator async contract.
Server/Diagnostics/DiagnosticPublisher.cs	Adds <returns> documentation for async publish method.
Server/BufferManager.cs	Adds <returns> documentation for buffer snapshot accessor.
.github/copilot-instructions.md	Updates contributor guidance to require <returns> tags.
.gitattributes	Adds LF line-ending enforcement to match .editorconfig.
.editorconfig	Re-enables SA1615/SA1623/SA1629 as warnings.

[Copilot]

Pull request overview

Copilot reviewed 24 out of 24 changed files in this pull request and generated no new comments.