- Separated deterministic replacement generation, placeholder derivation,
placeholder-range scanning and message-tree transforms out of the 2647-line
module; obfuscator.ts now holds the types and SecretObfuscator.
- ephemeralPlaceholderKey stays a single instance and both global regexes stay
beside the code that resets their lastIndex, so placeholder stability and
the security argument in the moved comments are preserved verbatim.
- Repointed every importer at the real modules rather than leaving a re-export
shim; the public ./secrets barrel exports the same 15 names as before.