[log] config: migrate logConfig from legacy log.New to project debug logger

[github-actions]

Summary

Migrates internal/config/config_core.go from the legacy log.New pattern to the project's standard debug logger (logger.New).

Changes

File modified: internal/config/config_core.go

Before

import (
    "fmt"
    "io"
    "log"
    "os"
    ...
)

// logger for config package
var logConfig = log.New(io.Discard, "[CONFIG] ", log.LstdFlags)

// SetDebug enables debug logging for config package
func SetDebug(enabled bool) {
    if enabled {
        logConfig = log.New(os.Stderr, "[CONFIG] ", log.LstdFlags)
    } else {
        logConfig = log.New(io.Discard, "[CONFIG] ", log.LstdFlags)
    }
}

After

import (
    "fmt"
    "os"
    ...
    "github.com/github/gh-aw-mcpg/internal/logger"
)

// logConfig is the debug logger for the config package.
// Enable with DEBUG=config:* or DEBUG=*.
var logConfig = logger.New("config:config")

Motivation

The config package was the last package in internal/ still using the legacy log.New(io.Discard, ...) pattern. This pattern required explicit SetDebug(true) calls (which were never made anywhere in the codebase) to see any output.

The project's logger.New pattern:

• Is controlled by the DEBUG env var (e.g. DEBUG=config:* or DEBUG=*)
• Writes colorized, time-diff output to stderr during development
• Also writes to the file logger (mcp-gateway.log) for production troubleshooting
• Is consistent with all other packages in the codebase

Impact

• The existing logConfig.Printf(...) calls in both config_core.go and config_stdin.go now route through the project's debug logger
• SetDebug is removed (was never called; no callers exist)
• io and log standard library imports removed from config_core.go
• Zero behavioral change in production (debug logs only appear when DEBUG env var matches)

Testing

• Build: go build ./... (no compilation errors)
• Tests: go test ./... (no regressions)
• Vet: go vet ./... (no issues)

Generated by Go Logger Enhancement · ● 5.8M · ◷

[Copilot]

Pull request overview

Migrates the config package’s debug logging in internal/config/config_core.go from a legacy log.New(io.Discard, ...) approach to the repo’s standard internal/logger debug logger, so config debug output can be controlled via DEBUG patterns.

Changes:

• Remove legacy logConfig initialization and SetDebug toggling.
• Introduce logConfig as a logger.New(...) instance controlled by DEBUG.

Show a summary per file

File	Description
internal/config/config_core.go	Replaces legacy stdlib logger + SetDebug with project debug logger instance.

Copilot's findings

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• Files reviewed: 1/1 changed files
• Comments generated: 1

[Copilot]

logConfig is initialized at package init via logger.New(...), which computes the enabled state once at construction time. Since the CLI sets DEBUG at runtime in internal/cmd/root.go (for -vv/-vvv), this logger will stay disabled even after DEBUG is set, so these config debug logs still won’t appear when users enable verbosity flags. Consider constructing the logger lazily after DEBUG is finalized (e.g., create it inside the load functions or behind a sync.Once getter), or adjust the logger implementation to re-evaluate DEBUG on each call.