feat(logging): add structured logging helpers with strong typing

[CalvinAllen]

Summary

Add helpers for creating strongly-typed, structured log events. Reduces string formatting errors and enables better log analysis in observability platforms.

Problem

Current logging requires manual string formatting and doesn't enforce structure:

// Easy to make mistakes, no compile-time checking
logger.LogInformation("User {UserId} performed {Action} on {Resource}", 
    userId, action, resource);

Proposed Solution

Option 1: Source Generator Approach

// Define log events as partial methods
public static partial class LogEvents
{
    [LogEvent(Level = LogLevel.Information, Message = "User {UserId} performed {Action}")]
    public static partial void UserAction(this ILogger logger, string userId, string action);
    
    [LogEvent(Level = LogLevel.Error, Message = "Operation {Operation} failed")]
    public static partial void OperationFailed(this ILogger logger, string operation, Exception ex);
}

// Usage - strongly typed!
VsixTelemetry.Logger.UserAction("user123", "save");
VsixTelemetry.Logger.OperationFailed("LoadProject", exception);

Option 2: Fluent Builder

VsixTelemetry.Log
    .Information("User performed action")
    .WithProperty("UserId", userId)
    .WithProperty("Action", action)
    .WithProperty("Resource", resource)
    .Write();

// Or for common patterns
VsixTelemetry.Log
    .Operation("LoadSolution")
    .Started();
    
VsixTelemetry.Log
    .Operation("LoadSolution") 
    .Succeeded(duration);
    
VsixTelemetry.Log
    .Operation("LoadSolution")
    .Failed(exception);

Option 3: Event Classes

public record UserActionEvent(string UserId, string Action, string Resource);

VsixTelemetry.LogEvent(new UserActionEvent("user123", "save", "document.cs"));
// Automatically extracts properties and formats message

Benefits

• Compile-time checking of log parameters
• Consistent property naming
• Better IntelliSense support
• Easier log analysis (consistent structure)