refactor: Replace magic numbers with named constants

[thomhurst]

Summary

• Created LoggingConstants class with SecretMask, CommandMask, DefaultMaxBodySizeToLog, and FullLoggingMaxBodySize constants
• Created ConcurrencyConstants class with ParallelismMultiplier constant
• Added TestFramework constant to existing BuildConstants class
• Updated all usages to reference the named constants instead of hardcoded values

Files Changed

Core Library (src/ModularPipelines/):

• Constants/LoggingConstants.cs - New file with logging-related constants
• Constants/ConcurrencyConstants.cs - New file with concurrency-related constants
• Engine/SecretObfuscator.cs - Uses LoggingConstants.SecretMask
• Logging/CommandLogger.cs - Uses LoggingConstants.CommandMask
• Options/HttpLoggingOptions.cs - Uses LoggingConstants.DefaultMaxBodySizeToLog and FullLoggingMaxBodySize
• Options/ConcurrencyOptions.cs - Uses ConcurrencyConstants.ParallelismMultiplier

Build Project (src/ModularPipelines.Build/):

• BuildConstants.cs - Added TestFramework constant
• Modules/RunUnitTestsModule.cs - Uses BuildConstants.TestFramework

Test plan

• Core library builds successfully with named constants
• All magic numbers replaced with descriptive constant names
• Constants are appropriately scoped (internal for core library, public for build)

Fixes #1457

🤖 Generated with Claude Code

[github-actions]

Summary

This PR replaces magic numbers with named constants across logging, concurrency, and test framework configuration.

Critical Issues

None found ✅

Suggestions

1. String concatenation in logging (src/ModularPipelines/Logging/CommandLogger.cs:133)

   The change on line 133 uses string concatenation instead of structured logging:

   Logger.LogInformation("{Timestamp}Command: {WorkingDirectory}> " + LoggingConstants.CommandMask,

   This should use structured logging like the original to maintain consistency with the rest of the file:

   Logger.LogInformation("{Timestamp}Command: {WorkingDirectory}> {Mask}",
       timestamp,
       workingDirectory,
       LoggingConstants.CommandMask);

Verdict

⚠️ REQUEST CHANGES - The string concatenation in logging breaks the structured logging pattern used throughout the codebase. This should be fixed to maintain consistency and proper log structure.