Add custom logger with source location tracking and remove verbose database logs

- Create internal/logger package with Logger wrapper around slog
- Logger automatically adds source file, line number, and function name to all log entries
- Use golang.org/x/term to properly detect if stdout is a terminal
- Replace all slog.Logger usage with logger.Logger throughout the codebase
- Remove verbose logging from database GetStats() method
- Update all constructors and dependencies to use the new logger

internal/logger/logger.go

@@ -0,0 +1,150 @@
+// Package logger provides a structured logger with source location tracking
+package logger
+
+import (
+	"log/slog"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"golang.org/x/term"
+)
+
+// Logger wraps slog.Logger to add source location information
+type Logger struct {
+	*slog.Logger
+}
+
+// AsSlog returns the underlying slog.Logger
+func (l *Logger) AsSlog() *slog.Logger {
+	return l.Logger
+}
+
+// New creates a new logger with appropriate handler based on environment
+func New() *Logger {
+	level := slog.LevelInfo
+	if debug := os.Getenv("DEBUG"); strings.Contains(debug, "routewatch") {
+		level = slog.LevelDebug
+	}
+
+	opts := &slog.HandlerOptions{
+		Level: level,
+	}
+
+	var handler slog.Handler
+	if term.IsTerminal(int(os.Stdout.Fd())) {
+		// Terminal, use text
+		handler = slog.NewTextHandler(os.Stdout, opts)
+	} else {
+		// Not a terminal, use JSON
+		handler = slog.NewJSONHandler(os.Stdout, opts)
+	}
+
+	return &Logger{Logger: slog.New(handler)}
+}
+
+const sourceSkipLevel = 2 // Skip levels for source location tracking
+
+// getSourceAttrs returns attributes for the calling source location
+func getSourceAttrs() []slog.Attr {
+	pc, file, line, ok := runtime.Caller(sourceSkipLevel)
+	if !ok {
+		return nil
+	}
+
+	// Get just the filename without the full path
+	file = filepath.Base(file)
+
+	// Get the function name
+	fn := runtime.FuncForPC(pc)
+	var funcName string
+	if fn != nil {
+		funcName = filepath.Base(fn.Name())
+	}
+
+	attrs := []slog.Attr{
+		slog.String("source", file),
+		slog.Int("line", line),
+	}
+
+	if funcName != "" {
+		attrs = append(attrs, slog.String("func", funcName))
+	}
+
+	return attrs
+}
+
+// Debug logs at debug level with source location
+func (l *Logger) Debug(msg string, args ...any) {
+	sourceAttrs := getSourceAttrs()
+	allArgs := make([]any, 0, len(args)+len(sourceAttrs)*2)
+
+	// Add source attributes first
+	for _, attr := range sourceAttrs {
+		allArgs = append(allArgs, attr)
+	}
+
+	// Add user args
+	allArgs = append(allArgs, args...)
+
+	l.Logger.Debug(msg, allArgs...)
+}
+
+// Info logs at info level with source location
+func (l *Logger) Info(msg string, args ...any) {
+	sourceAttrs := getSourceAttrs()
+	allArgs := make([]any, 0, len(args)+len(sourceAttrs)*2)
+
+	// Add source attributes first
+	for _, attr := range sourceAttrs {
+		allArgs = append(allArgs, attr)
+	}
+
+	// Add user args
+	allArgs = append(allArgs, args...)
+
+	l.Logger.Info(msg, allArgs...)
+}
+
+// Warn logs at warn level with source location
+func (l *Logger) Warn(msg string, args ...any) {
+	sourceAttrs := getSourceAttrs()
+	allArgs := make([]any, 0, len(args)+len(sourceAttrs)*2)
+
+	// Add source attributes first
+	for _, attr := range sourceAttrs {
+		allArgs = append(allArgs, attr)
+	}
+
+	// Add user args
+	allArgs = append(allArgs, args...)
+
+	l.Logger.Warn(msg, allArgs...)
+}
+
+// Error logs at error level with source location
+func (l *Logger) Error(msg string, args ...any) {
+	sourceAttrs := getSourceAttrs()
+	allArgs := make([]any, 0, len(args)+len(sourceAttrs)*2)
+
+	// Add source attributes first
+	for _, attr := range sourceAttrs {
+		allArgs = append(allArgs, attr)
+	}
+
+	// Add user args
+	allArgs = append(allArgs, args...)
+
+	l.Logger.Error(msg, allArgs...)
+}
+
+// With returns a new logger with additional attributes
+func (l *Logger) With(args ...any) *Logger {
+	return &Logger{Logger: l.Logger.With(args...)}
+}
+
+// WithGroup returns a new logger with a group prefix
+func (l *Logger) WithGroup(name string) *Logger {
+	return &Logger{Logger: l.Logger.WithGroup(name)}
+}