Summary

This PR migrates the codebase from using the pingcap/log wrapper around go.uber.org/zap to the standard library's log/slog package. This reduces external dependencies and leverages Go's built-in structured logging capabilities.

Key Changes

• Logging imports: Replaced github.com/pingcap/log and go.uber.org/zap with log/slog
• Logging calls: Updated all logging statements to use slog API:
  • log.Warn() → slog.Warn()
  • log.Error() → slog.Error()
  • log.Debug() → slog.Debug()
  • log.Fatal() → slog.Error() + os.Exit(1)
• Attribute formatting: Converted zap attributes to slog equivalents:
  • zap.String() → slog.String()
  • zap.Int() → slog.Int()
  • zap.Error() → slog.Any("error", err)
  • zap.Stack() → slog.String("stack", string(debug.Stack()))
• Dependencies: Removed github.com/pingcap/log and go.uber.org/zap from go.mod
• Files modified: terror/terror.go and charset/charset.go

Notable Implementation Details

• Stack traces are now explicitly captured using runtime/debug.Stack() instead of relying on zap's automatic stack capture
• The MustNil() function now calls os.Exit(1) after logging instead of using log.Fatal() to maintain the same behavior
• All structured logging attributes are preserved with equivalent slog field types

https://claude.ai/code/session_01YLqL18zVJuHKeozjDQtb1u