…pm#502)

Closes pnpm#497.

## Summary

Adds per-registry TLS overrides keyed by nerf-darted `.npmrc` URI, the natural follow-up to pnpm#490's top-level TLS keys. Corporate environments running a private Verdaccio (or any registry with its own self-signed cert) can now pin scoped `:cafile=…` / `:cert=…` / `:key=…` per host without disabling strict-ssl globally.

Three commits, layered:

- **`feat(network)`** (eff1248e): adds `RegistryTls` + `PerRegistryTls` types in `pacquet-network` plus the lookup machinery — `pick_for_url` ports pnpm's [5-step `pickSettingByUrl`](https://github.com/pnpm/pnpm/blob/94240bc046/network/fetch/src/dispatcher.ts#L338-L375) exactly (exact > nerf-dart > no-port > shorter prefix > recursive no-port retry). `ThrottledClient::for_installs` gains a third `&PerRegistryTls` parameter and pre-builds one reqwest `Client` per non-empty override. New `acquire_for_url(url: &str)` routes per-request; `acquire()` keeps the default-client behavior for callers without a URL.

- **`feat(config)`** (4e69868a): `NpmrcAuth` parses the six per-registry TLS suffixes (`:ca`, `:cafile`, `:cert`, `:certfile`, `:key`, `:keyfile`) matching pnpm's `SSL_SUFFIX_RE` and applies onto `Config.tls_by_uri`. `*file` variants read from disk at parse time (silent on error); inline values get `\\n` → `\n` expansion. `:cert` and `:certfile` share the same `tls.cert` slot — last-write-wins inside one `.npmrc`.

- **`refactor(tarball,registry)`** (5f9cae93): three production call sites (registry metadata + version-tag fetches, plus two tarball download paths) move from `acquire()` to `acquire_for_url(url)` so the per-registry routing actually fires.

## Parity policy

Bug-for-bug with pnpm v11 ([SHA 94240bc](https://github.com/pnpm/pnpm/blob/94240bc046/config/reader/src/getNetworkConfigs.ts)):

- **Field-by-field override**, not replace-all. Each scoped `ca` / `cert` / `key` overrides its top-level counterpart independently (mirroring upstream's `{ ...opts, ...sslConfig }` spread at `dispatcher.ts:143,264`). `strict_ssl` and `local_address` stay top-level-only — pnpm's regex doesn't recognize scoped versions.
- **`ca` as `Option<String>`, not `Vec<String>`**: per-registry `ca` is a single string (possibly with concatenated `-----END CERTIFICATE-----` delimiters) — `reqwest::Certificate::from_pem` accepts both shapes.
- **Inline `\\n` expansion only on per-registry**: pnpm applies `value.replace(/\\n/g, '\n')` to scoped values but not to top-level `ca=`. The divergence is intentional and matches upstream.
- **Lax URI prefix check**: `foo:cert=…` (no `//` prefix) is accepted into the map with `uri_prefix = "foo"`. It never matches a real nerf-darted URL so the entry is dropped at lookup time, but storing it keeps byte-for-byte parsing parity with `tryParseSslKey`.

## Reviewer flags

- **Per-registry clients duplicate connection pools.** Each unique override gets its own `reqwest::Client` and therefore its own connection pool. With N per-registry overrides the worker holds N+1 pools instead of one. The semaphore still bounds *concurrent in-flight requests* globally, but socket churn between registries with different TLS configs is now per-client. In practice most users have ≤2 overrides; if this becomes an issue we'd need to switch to rustls + custom certificate verifier (tracked under pnpm#499).
- **`acquire_for_url` takes `&str` rather than `&Url`** so the existing `format!("{registry}{name}")` call sites don't need to round-trip through `Url::parse`. The lookup itself works on the raw string form via `nerf_dart`.

…pm#502)

Closes pnpm#497.

## Summary

Adds per-registry TLS overrides keyed by nerf-darted `.npmrc` URI, the natural follow-up to pnpm#490's top-level TLS keys. Corporate environments running a private Verdaccio (or any registry with its own self-signed cert) can now pin scoped `:cafile=…` / `:cert=…` / `:key=…` per host without disabling strict-ssl globally.

Three commits, layered:

- **`feat(network)`** (eff1248e): adds `RegistryTls` + `PerRegistryTls` types in `pacquet-network` plus the lookup machinery — `pick_for_url` ports pnpm's [5-step `pickSettingByUrl`](https://github.com/pnpm/pnpm/blob/94240bc046/network/fetch/src/dispatcher.ts#L338-L375) exactly (exact > nerf-dart > no-port > shorter prefix > recursive no-port retry). `ThrottledClient::for_installs` gains a third `&PerRegistryTls` parameter and pre-builds one reqwest `Client` per non-empty override. New `acquire_for_url(url: &str)` routes per-request; `acquire()` keeps the default-client behavior for callers without a URL.

- **`feat(config)`** (4e69868a): `NpmrcAuth` parses the six per-registry TLS suffixes (`:ca`, `:cafile`, `:cert`, `:certfile`, `:key`, `:keyfile`) matching pnpm's `SSL_SUFFIX_RE` and applies onto `Config.tls_by_uri`. `*file` variants read from disk at parse time (silent on error); inline values get `\\n` → `\n` expansion. `:cert` and `:certfile` share the same `tls.cert` slot — last-write-wins inside one `.npmrc`.

- **`refactor(tarball,registry)`** (5f9cae93): three production call sites (registry metadata + version-tag fetches, plus two tarball download paths) move from `acquire()` to `acquire_for_url(url)` so the per-registry routing actually fires.

## Parity policy

Bug-for-bug with pnpm v11 ([SHA 94240bc](https://github.com/pnpm/pnpm/blob/94240bc046/config/reader/src/getNetworkConfigs.ts)):

- **Field-by-field override**, not replace-all. Each scoped `ca` / `cert` / `key` overrides its top-level counterpart independently (mirroring upstream's `{ ...opts, ...sslConfig }` spread at `dispatcher.ts:143,264`). `strict_ssl` and `local_address` stay top-level-only — pnpm's regex doesn't recognize scoped versions.
- **`ca` as `Option<String>`, not `Vec<String>`**: per-registry `ca` is a single string (possibly with concatenated `-----END CERTIFICATE-----` delimiters) — `reqwest::Certificate::from_pem` accepts both shapes.
- **Inline `\\n` expansion only on per-registry**: pnpm applies `value.replace(/\\n/g, '\n')` to scoped values but not to top-level `ca=`. The divergence is intentional and matches upstream.
- **Lax URI prefix check**: `foo:cert=…` (no `//` prefix) is accepted into the map with `uri_prefix = "foo"`. It never matches a real nerf-darted URL so the entry is dropped at lookup time, but storing it keeps byte-for-byte parsing parity with `tryParseSslKey`.

## Reviewer flags

- **Per-registry clients duplicate connection pools.** Each unique override gets its own `reqwest::Client` and therefore its own connection pool. With N per-registry overrides the worker holds N+1 pools instead of one. The semaphore still bounds *concurrent in-flight requests* globally, but socket churn between registries with different TLS configs is now per-client. In practice most users have ≤2 overrides; if this becomes an issue we'd need to switch to rustls + custom certificate verifier (tracked under pnpm#499).
- **`acquire_for_url` takes `&str` rather than `&Url`** so the existing `format!("{registry}{name}")` call sites don't need to round-trip through `Url::parse`. The lookup itself works on the raw string form via `nerf_dart`.