iconvex_retro

# Iconvex Retro TDD log

## RED

- Added frozen-surface contracts before runtime code: 274 rows split into 192
  byte registrations, 23 logical codecs, 57 packed profiles, and 2 providers.
- Added lifecycle, provider ownership, late-collision rollback, manifest-builder,
  package-boundary, and packed transport contracts.
- First run: 6 tests, 6 failures because the facade, codecs, packed API, and
  generator did not yet exist.

## GREEN

- Ported and renamed the Retro runtime, macro helpers, table support, fixtures,
  source assets, and package-owned providers.
- Generated the public facade and all three inventories from the frozen TSV.
- Installed the full package through one `Iconvex.Extension` transaction.
- Ported the original Retro-family tests and narrowed mixed-family assertions
  to the manifest owner without adding a Specs or Archive runtime dependency.
- Added exact MSB/LSB packed profiles and preserved physical bit offsets.
- Added an independent frozen-source oracle covering all 192 byte codecs,
  49,152 one-byte inputs, each decoded repertoire and error policy, every
  12-bit card mask, and representative DEC Radix-50 transports.
- Isolated benchmark samples in fresh BEAM processes so garbage-collection
  history cannot create false nonlinear-scaling failures.
- Final verification: 281 tests, 0 failures.

Release verification commands:

```console
ICONVEX_PATH=../iconvex mix test
elixir tools/generate_surface_module.exs --check
MIX_ENV=prod ICONVEX_PATH=../iconvex mix compile --warnings-as-errors
env -u ICONVEX_PATH mix hex.build
```