feat: add antislop option - #861

Description

Adds an opt-in, experimental antislop factory option to guard against low-value code patterns commonly introduced by AI agents, inspired by this writeup on keeping AI-authored code clean.

• Enables all rules from eslint-plugin-slop v0.1.1 (including the new no-jargon and prefer-jsdoc; the plugin ships no preset, so the set is maintained here).
• Enables an in-house maintained subset of eslint-plugin-sonarjs focused on redundant and duplicated code (e.g. no-identical-functions, no-duplicated-branches, no-commented-code, cognitive-complexity), deliberately excluding security/AWS/test/regex rules that overlap with existing configs, and type-aware rules so it works without tsconfigPath.
• Turns ts/no-explicit-any on (error) when TypeScript is enabled; the antislop config is composed after the TypeScript config so the override takes effect.
• The option accepts an object to toggle each plugin: sonarjs?: boolean and slop?: boolean | OptionsSlop — passing an object enables eslint-plugin-slop and is forwarded to it via settings.slop (e.g. inspection mode).
• Marked @experimental: the enabled rule set is maintained in-house and may change in any release without following semver.
• Both plugins are optional peer dependencies, installed on demand via the usual ensurePackages prompt.
• Supports antislop: { overrides: {...} } like other integrations.
• README documents the option and recommends pairing it with jscpd and knip, since linters only see one file at a time.

Note: 7 factory snapshots were already stale on main (from the earlier pnpm blank-lines feature) and got regenerated together with the new antfu/antislop/rules entries.

This PR was created with the help of an agent.