feat(client): parse unix:// URLs in parseURL

[nkaradzhov]

Accept unix://[user[:password]@]/path/to/sock[?db=N] so users can configure UNIX-domain-socket connections via a URL string, matching the scheme supported by redis-py. The underlying socket layer already handles UDS via socket.path; this only adds the URL convenience layer.

WHATWG URL refuses to parse an authority without a host on non-special schemes, so the unix branch uses a small regex instead of new URL.

Closes #2530

Description

Describe your pull request here

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Checklist

• Does npm test pass with this change (including linting)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

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Note

Medium Risk
Changes connection URL parsing to accept unix:// schemes, which can affect how clients derive socket/auth/db options and may reject previously-accepted edge-case URLs. Scope is limited and covered by new unit tests and docs updates.

Overview
Adds support for configuring UNIX domain socket connections via url by extending RedisClient.parseURL to parse unix://[user[:password]@]/path/to/socket[?db=N] (including decoding percent-encoded paths, optional credentials, and db query param validation).

Updates docs to advertise the new unix:// URL format, and adds a focused test suite for valid/invalid UNIX-socket URL cases. Includes small TypeScript typing cleanups (ProxyClient generics, @ts-expect-error, safer MULTI constructor cast) and a couple of targeted eslint suppressions for any push handlers.

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