Perf

[jessehouwing]

This pull request makes significant improvements to the CommandInfoCache and related command metadata handling in the ScriptAnalyzer engine. The main focus is on thread safety, improved caching, and more robust handling of PowerShell command metadata, especially for parameter information. It introduces a new CommandParameterSnapshot class to safely cache detached parameter metadata, and it refactors how command and parameter information is retrieved and cached to avoid threading issues with the PowerShell engine.

Thread safety and runspace management:

• Refactored CommandInfoCache to use a single Runspace and a re-entrant lock (_runspaceLock) instead of a RunspacePool, ensuring all PowerShell engine access is serialized and thread-safe. This prevents transient failures due to PowerShell's lack of thread safety. [1] [2]
• Updated disposal logic to ensure the runspace cannot be disposed while lookups are in flight, further improving thread safety.

Command and parameter metadata caching:

• Added caching for parameter snapshots and mandatory parameter names using new concurrent dictionaries, reducing redundant metadata queries and improving performance. [1] [2]
• Introduced the CommandParameterSnapshot class to safely store and retrieve parameter facts without needing to access PowerShell runspace objects, avoiding runspace affinity issues.

Improved error handling and cache eviction:

• Enhanced error handling to distinguish between command resolution errors and other exceptions, ensuring failed lookups are not cached and can be retried. Faulted cache entries are now evicted to prevent persistent failures. [1] [2] [3]

Helper and analysis improvements:

• Updated Helper.GetExportedFunction to use the new parameter snapshot mechanism for Export-ModuleMember, eliminating dynamic parameter resolution and improving reliability in multi-threaded analysis. [1] [2]
• Added GetModuleManifestForAnalysis to share module manifest validation between rules during a single analysis, reducing redundant work.

Miscellaneous:

• Fixed hash code calculation in CommandLookupKey to use StringComparer.OrdinalIgnoreCase for correctness.

These changes collectively make command and parameter metadata handling safer, faster, and more robust, especially under concurrent analysis scenarios.## PR Summary
when the PR is ready.