Update analyzers for handlers

[viceroypenguin]

No description provided.

[Copilot]

Pull Request Overview

This PR updates the handler analyzers to support both static and instance handler methods, replacing the previous static-only requirement. The changes include new validation rules for instance handlers and comprehensive test coverage for both handler types.

• Removes the requirement for handler methods to be static, allowing both static and instance handlers
• Adds new analyzer rules for instance handler validation (sealed classes, private members, parameter validation)
• Updates existing analyzer logic to handle both static and instance handler patterns

Reviewed Changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
HandlerClassAnalyzer.cs	Core analyzer logic updated to support both static and instance handlers with new validation rules
TransformHandler.cs	Updated ValueTask return type validation logic with more precise namespace checking
DiagnosticIds.cs	Added new diagnostic IDs and removed the static method requirement ID
Multiple test files	Comprehensive test coverage for both static and instance handler scenarios
Immediate.Handlers.Analyzers.md	Removed documentation for the static method requirement
AnalyzerReleases.Unshipped.md	Documents added and removed analyzer rules
launchSettings.json	Updated project paths for debugging

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ
...mediate.Handlers.Analyzers/HandlerClassAnalyzer.cs	99.32% <100.00%> (+1.85%)	⬆️
.../Immediate.Handlers.Generators/TransformHandler.cs	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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