* refactor(pnpr): rename pnpm-registry to pnpr
Rename the registry server across the board to match the npm wrapper
package name, which was already `@pnpm/pnpr`.
- crate `pnpm-registry` -> `pnpr`, `pnpm-registry-fixtures` -> `pnpr-fixtures`
- binaries `pnpm-registry` -> `pnpr`, `pnpm-registry-prepare` -> `pnpr-prepare`
- module paths and log targets `pnpm_registry::*` -> `pnpr::*`
- binary-locating env vars `PNPM_REGISTRY_BIN` -> `PNPR_BIN`,
`PNPM_REGISTRY_PREPARE_BIN` -> `PNPR_PREPARE_BIN`
- top-level directory `registry/` -> `pnpr/` (crates, npm wrapper, fixtures)
The registry-mock storage concept is intentionally left as-is:
`PNPM_REGISTRY_MOCK_PORT`/`PNPM_REGISTRY_MOCK_STORAGE`/`PNPM_REGISTRY_STORAGE`,
the `~/.cache/pnpm-registry/storage` path + benchmark cache keys, and the
external `pnpm-registry-mock` npm package referenced in test fixtures.
* style(pnpr): rustfmt import grouping after rename
* ci(pnpr): point typos at pnpr instead of removed registry dir
* chore(pnpr): update pre-push path filter from registry to pnpr