chore(web): add ESLint rules for i18n JSON validation

[hyoban]

Summary

• Add valid-i18n-keys rule to ensure i18n JSON keys are flat and don't conflict (no key can be a prefix of another key)
• Add no-extra-keys rule to ensure non-English JSON files don't have keys missing from en-US (with autofix support)
• Add utility function to handle JSON files with trailing commas

Test plan

• Run pnpm lint to verify rules work correctly
• Verify rules catch invalid key structures in JSON files
• Verify autofix removes extra keys from non-English translations

🤖 Generated with Claude Code

[gemini-code-assist]

Summary of Changes

Hello @hyoban, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the internationalization (i18n) workflow by introducing new ESLint rules specifically designed for validating i18n JSON files. These rules aim to enforce consistency in key structures and prevent discrepancies between different language translations, thereby improving the maintainability and reliability of the localization process.

Highlights

• New ESLint Rule: valid-i18n-keys: Introduced a new ESLint rule to ensure i18n JSON keys are flat and do not conflict, meaning no key can be a prefix of another key (e.g., 'foo' and 'foo.bar' cannot both exist).
• New ESLint Rule: no-extra-keys: Added an ESLint rule that verifies non-English i18n JSON files do not contain keys that are missing from their en-US counterparts. This rule also includes autofix support to remove such extra keys.
• JSON Utility Function: A new utility function has been added to robustly handle JSON files that might contain trailing commas, ensuring they can be parsed correctly.

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[gemini-code-assist]

Code Review

This pull request introduces valuable ESLint rules for validating i18n JSON files, which is a great step towards maintaining translation quality. The new valid-i18n-keys and no-extra-keys rules cover important validation scenarios. My review focuses on improving the robustness, efficiency, and developer experience of these new rules. I've identified opportunities to improve JSON parsing with trailing commas, refine the autofix logic to avoid conflicts, make error reporting more descriptive, and enhance the efficiency of the key validation logic. The cleanJsonText utility can also be made more robust. Please see my detailed comments for specific suggestions.

[Copilot]

Pull request overview

This PR adds two custom ESLint rules to validate i18n JSON files: one to ensure keys don't conflict with each other as prefixes, and another to prevent non-English translations from having extra keys not present in the English source files.

• Add valid-i18n-keys rule to detect conflicting key structures
• Add no-extra-keys rule with autofix to remove extra keys from non-English translations
• Add utility function to handle JSON files with trailing commas

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
web/eslint.config.mjs	Reorganizes i18n-related ESLint rules and adds the two new validation rules for JSON files
web/eslint-rules/utils.js	Adds utility function to clean trailing commas from JSON text before parsing
web/eslint-rules/rules/valid-i18n-keys.js	Implements rule to validate that i18n keys don't create prefix conflicts
web/eslint-rules/rules/no-extra-keys.js	Implements rule to detect and autofix extra keys in non-English translation files
web/eslint-rules/index.js	Exports the two new rules in the plugin

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