feat: add @interweb/inflection library for PostGraphile-compatible pluralization

[pyramation]

Summary

Adds a new @interweb/inflection package that provides pluralization and singularization utilities with PostGraphile-compatible Latin suffix handling. This library is intended to be shared between graphile-simple-inflector and @constructive-io/graphql-codegen to ensure consistent inflection behavior across the codebase.

The library includes:

• singularize/pluralize with Latin suffix overrides in both directions (schemata↔schema, criteria↔criterion, etc.)
• singularizeLast/pluralizeLast for compound word handling (only transforms the last word)
• distinctPluralize for cases where singular equals plural
• Case transformations (lcFirst, ucFirst, fixCapitalisedPlural)
• GraphQL naming helpers (toFieldName, toQueryName)

Updates since last revision

Added LATIN_PLURAL_OVERRIDES to the pluralize function so that Latin-style plurals are used (e.g., schema → schemata, criterion → criteria). This maintains backward compatibility with PostGraphile's expected GraphQL field names. Without this fix, upgrading would cause breaking changes where fields like schemata would become schemas.

Review & Testing Checklist for Human

• Verify the LATIN_PLURAL_OVERRIDES list matches LATIN_SUFFIX_OVERRIDES (they should be inverses of each other)
• Test that pluralize('schema') returns 'schemata' and pluralize('Schema') returns 'Schemata' (case preservation)
• Review the changeLastWord regex pattern in pluralize.ts - this handles compound words and is critical for correct behavior
• Confirm package name @interweb/inflection is the desired name before publishing

Test plan: Run cd packages/inflection && pnpm test locally. After publishing, update graphile-simple-inflector and verify that GraphQL schemas still use schemata (not schemas) for the Database type's relation field.

Notes

This is the first of multiple PRs - the next steps are to:

1. Update graphile-simple-inflector in constructive repo to use this library
2. Update graphql-codegen to use this library and remove the duplicate pluralize.ts

Link to Devin run: https://app.devin.ai/sessions/0a2a8e7889894852863ad967c5e79636
Requested by: Dan Lynch (@pyramation)

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