fix: expose English language pack

[alyldas]

Summary

• Move the reviewed English dictionary and filter implementation into src/languages/en.
• Export the English dictionary, lazy read-only shared filter, and mutable filter factory from the package entrypoint.
• Keep the Russian shared default unchanged while making the English implementation available in the published distribution.
• Add source, type-level, and runtime distribution coverage for the public English API.
• Update package metadata, policy documentation, and the private example to use the package-owned implementation.

Validation

• npm test -- --run tests/english-language-pack.spec.ts tests/api.spec.ts tests/language-dictionaries.spec.ts tests/scanner.spec.ts
• npm run check
• npm pack --dry-run --json

Benchmark Evidence

Baseline origin/main:

• create filter: 7.6264 avg ms
• short clean: 0.0285 avg ms
• long clean: 4.2932 avg ms
• short match: 0.0038 avg ms

This branch:

• create filter: 7.6255 avg ms
• short clean: 0.0262 avg ms
• long clean: 4.3215 avg ms
• short match: 0.0037 avg ms

The English shared filter is initialized lazily, and the existing default matching path remains within normal benchmark variance.

Compatibility Notes

• Existing public APIs and the Russian shared default remain unchanged.
• English rules are opt-in through englishProfanityFilter or createEnglishProfanityFilter() and are not added to filter.
• The shared English export is read-only; the factory returns isolated mutable filters with the existing runtime mutation contract.

Closes #148

No publish, no merge, no tag/release.

[chatgpt-codex-connector]

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[alyldas]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🚀

Reviewed commit: 47dccb6be5

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