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/streamer/streamer_test.go

@@ -3,12 +3,12 @@ package streamer
 import (
 	"testing"
 
+	"git.eeqj.de/sneak/routewatch/internal/logger"
 	"git.eeqj.de/sneak/routewatch/internal/metrics"
-	"log/slog"
 )
 
 func TestNewStreamer(t *testing.T) {
-	logger := slog.Default()
+	logger := logger.New()
 	metricsTracker := metrics.New()
 	s := New(logger, metricsTracker)