Codex Sync Kit v0.1.6

TOML redaction correctness patch. Preserves quoted path and plugin keys while recursively redacting secret values, keeping sanitized config.toml parseable for restore. Includes all v0.1.5 hardening: symlink/path-boundary enforcement, stronger secret filename blocking, configured-vault remote validation, manifest-checked restore, safer plugin prompts, private-vault validation, and automatic Codex plugin registration.