chore: pkg imported more than once - #263

…nhancements

Module renamed from github.com/buger/jsonparser to github.com/securityguy/jsonparser.

Security fixes:
- Fix GO-2026-4514: Delete() panics on malformed JSON (negative slice index DoS)
- Update Dockerfile base image from golang:1.6 to golang:1.21

Bug fixes:
- Fix EachKey failing to extract values from arrays of strings (PR buger#180)
- Remove duplicate import in parser_test.go (PR buger#263)

New APIs (all additive):
- ArrayEach callback now accepts *error for early termination; DoneError sentinel added (PR buger#134)
- DeleteOnOrig: in-place deletion variant with no allocation (PR buger#256)
- ArrayIterator: lazy closure-based array iteration (PR buger#254)
- GetRaw, EachRawKey: raw JSON byte extraction without type parsing (PR buger#250)

Other:
- go.mod bumped to go 1.18
- benchmark/go.mod updated with replace directive pointing to local module
- CLAUDE.md added for Claude Code guidance

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…#268)

- parser_test.go had both "fmt" and _ "fmt" imports — removed the
  blank duplicate (from PR #263 by @testwill)
- Dockerfile was pinned to Go 1.6 (broken) — updated to Go 1.25 and
  moved WORKDIR/ADD before dependency fetches for better layer caching
  (from PR #268 by @kai5263499)