feat: Add configurable log level filtering

[ssestak]

Summary

• Add configurable minimum log level threshold to LoggerConfiguration
• Implement native os.log filtering behavior (only logs at or above threshold are shown)
• Support for debug, info, error, and fault log levels

Changes

New LogLevel Enum

• .debug - Show all logs (lowest priority)
• .info - Show info, error, and fault logs
• .error - Show error and fault logs only
• .fault - Show only fault logs (highest priority)

Updated LoggerConfiguration

• Added logLevel parameter (defaults to .debug for backward compatibility)
• Platform-specific initializers for os.log availability
• Implements shouldLog() method for threshold checking

Updated FTNetworkTracer

• Check log level threshold before logging
• Only logs entries that meet or exceed configured minimum level

Example Usage

// Only log errors and faults in production
let logger = LoggerConfiguration(
    subsystem: "com.yourapp",
    category: "network",
    logLevel: .error
)

let tracer = FTNetworkTracer(logger: logger, analytics: analytics)

Test Plan

• All existing tests pass (67 tests)
• Build succeeds on macOS
• Cross-platform compatibility (conditional compilation)

Documentation

• Added inline documentation for LogLevel enum
• Updated LoggerConfiguration docs with logLevel parameter

🤖 Generated with Claude Code