Implement structured logging with slog

- Replace zerolog with Go's standard slog package
- Add ColorHandler for terminal color output
- Add context-aware logging system
- Format attributes on the same line as log messages
- Use green color for INFO level logs
- Set up context value extraction helpers

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

db/db.go

@@ -1,140 +0,0 @@
-package db
-
-import (
-	"encoding/json"
-	"fmt"
-	"os"
-	"strconv"
-	"time"
-
-	"gemini-grc/common/snapshot"
-	commonUrl "gemini-grc/common/url"
-	"gemini-grc/config"
-	"gemini-grc/logging"
-	"github.com/antanst/go_errors"
-	_ "github.com/jackc/pgx/v5/stdlib" // PGX driver for PostgreSQL
-	"github.com/jmoiron/sqlx"
-	"github.com/lib/pq"
-)
-
-func ConnectToDB() (*sqlx.DB, error) {
-	connStr := fmt.Sprintf("postgres://%s:%s@%s:%s/%s", //nolint:nosprintfhostport
-		os.Getenv("PG_USER"),
-		os.Getenv("PG_PASSWORD"),
-		os.Getenv("PG_HOST"),
-		os.Getenv("PG_PORT"),
-		os.Getenv("PG_DATABASE"),
-	)
-
-	// Create a connection pool
-	db, err := sqlx.Open("pgx", connStr)
-	if err != nil {
-		return nil, go_errors.NewFatalError(fmt.Errorf("unable to connect to database with URL %s: %w", connStr, err))
-	}
-	// TODO move PG_MAX_OPEN_CONNECTIONS to config env variables
-	maxConnections, err := strconv.Atoi(os.Getenv("PG_MAX_OPEN_CONNECTIONS"))
-	if err != nil {
-		return nil, go_errors.NewFatalError(fmt.Errorf("unable to set DB max connections: %w", err))
-	}
-	db.SetMaxOpenConns(maxConnections)
-	err = db.Ping()
-	if err != nil {
-		return nil, go_errors.NewFatalError(fmt.Errorf("unable to ping database: %w", err))
-	}
-
-	logging.LogDebug("Connected to database")
-	return db, nil
-}
-
-// IsDeadlockError checks if the error is a PostgreSQL deadlock error.
-func IsDeadlockError(err error) bool {
-	err = go_errors.Unwrap(err)
-	var pqErr *pq.Error
-	if go_errors.As(err, &pqErr) {
-		return pqErr.Code == "40P01" // PostgreSQL deadlock error code
-	}
-	return false
-}
-
-func GetRandomUrls(tx *sqlx.Tx) ([]string, error) {
-	var urls []string
-	err := tx.Select(&urls, SQL_SELECT_RANDOM_URLS, config.CONFIG.WorkerBatchSize)
-	if err != nil {
-		return nil, go_errors.NewFatalError(err)
-	}
-	return urls, nil
-}
-
-func GetRandomUrlsWithBasePath(tx *sqlx.Tx) ([]string, error) {
-	SqlQuery := `SELECT url FROM snapshots WHERE url ~ '^[^:]+://[^/]+/?$' ORDER BY RANDOM() LIMIT $1`
-	var urls []string
-	err := tx.Select(&urls, SqlQuery, config.CONFIG.WorkerBatchSize)
-	if err != nil {
-		return nil, go_errors.NewFatalError(err)
-	}
-	return urls, nil
-}
-
-func InsertURL(tx *sqlx.Tx, url string) error {
-	logging.LogDebug("Inserting URL %s", url)
-	query := SQL_INSERT_URL
-	normalizedURL, err := commonUrl.ParseURL(url, "", true)
-	if err != nil {
-		return err
-	}
-	a := struct {
-		Url       string
-		Host      string
-		Timestamp time.Time
-	}{
-		Url:       normalizedURL.Full,
-		Host:      normalizedURL.Hostname,
-		Timestamp: time.Now(),
-	}
-	_, err = tx.NamedExec(query, a)
-	if err != nil {
-		return go_errors.NewFatalError(fmt.Errorf("cannot insert URL: database error %w URL %s", err, url))
-	}
-	return nil
-}
-
-func DeleteURL(tx *sqlx.Tx, url string) error {
-	logging.LogDebug("Deleting URL %s", url)
-	query := SQL_DELETE_URL
-	_, err := tx.Exec(query, url)
-	if err != nil {
-		return go_errors.NewFatalError(fmt.Errorf("cannot delete URL: database error %w URL %s", err, url))
-	}
-	return nil
-}
-
-func OverwriteSnapshot(tx *sqlx.Tx, s *snapshot.Snapshot) (err error) {
-	if config.CONFIG.DryRun {
-		marshalled, err := json.MarshalIndent(s, "", "  ")
-		if err != nil {
-			return go_errors.NewFatalError(fmt.Errorf("JSON serialization error for %v", s))
-		}
-		logging.LogDebug("Would upsert snapshot %s", marshalled)
-		return nil
-	}
-	query := SQL_UPSERT_SNAPSHOT
-	rows, err := tx.NamedQuery(query, s)
-	if err != nil {
-		return go_errors.NewFatalError(fmt.Errorf("cannot overwrite snapshot: %w", err))
-	}
-	defer func() {
-		_err := rows.Close()
-		if err == nil && _err != nil {
-			err = go_errors.NewFatalError(fmt.Errorf("cannot overwrite snapshot: error closing rows: %w", err))
-		}
-	}()
-	if rows.Next() {
-		var returnedID int
-		err = rows.Scan(&returnedID)
-		if err != nil {
-			return go_errors.NewFatalError(fmt.Errorf("cannot overwrite snapshot: error scanning rows: %w", err))
-		}
-		s.ID = returnedID
-	}
-	return nil
-}