### `wai upscale` and `wai tonemap`: an exact derivation from the command line, with its record and its check

- **`wai upscale run`** (`media.upscale`) upscales an 8-bit RGB PNG under a prior, and with `--record` signs the record
  and writes the input's envelope it names. **`wai upscale verify`** (`upscale.verify`) recomputes the record from them
  under `require-proof`, and holds the picture to it.
- **`wai tonemap run`** (`media.tonemap`) renders a still's gain map at the headrooms named, and with `--record` signs
  the record. **`wai tonemap verify`** (`tonemap.verify`) recomputes it from its envelope, and holds the renditions to it.
- The library functions under them, `exact_upscale::make` and `exact_tonemap::make`, return the record's body for a
  caller to sign. `exact_upscale` now also needs `png_still` and `receipt_claims`. The catalogue's verbs gain `upscale`
  and `tonemap`.

