Remove dead code: splitLines loop, unused methods (gt-2g130)

- polecat.go: Remove unreachable first loop in splitLines (was using filepath.SplitList incorrectly)
- townlog/logger.go: Remove unused Event.JSON() method and json import
- lock/lock.go: Remove unused ErrStaleLock error variable
- refinery/manager.go: Remove unused getTestCommand() method

Note: witness.StatePaused is actually used by cmd/witness.go, not dead code.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/townlog/logger.go

@@ -2,7 +2,6 @@
 package townlog
 
 import (
-	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -272,12 +271,6 @@ func splitLines(s string) []string {
 	return lines
 }
 
-// LogEventJSON writes an event in JSON format for machine parsing.
-// Returns the JSON representation.
-func (e Event) JSON() ([]byte, error) {
-	return json.Marshal(e)
-}
-
 // TailEvents returns the last n events from the log.
 func TailEvents(townRoot string, n int) ([]Event, error) {
 	events, err := ReadEvents(townRoot)