fix(naming): respect casing of top-level names that collide with acronym dictionary

[schani]

Bug

Top-level type name capitalization was not respected when the name (case-insensitively) matched an entry in quicktype's built-in acronym dictionary. For example:

node dist/index.js --lang ts --just-types -t Acme --src-lang schema --src schema.json

produced export interface ACME { ... } instead of the expected export interface Acme { ... }, because "acme" happens to be in the acronym dictionary and the default TypeScript pascal acronym style all-uppercases any word flagged as an acronym — even when the input word was not actually written in all-caps.

Root cause

In splitIntoWords (packages/quicktype-core/src/support/Strings.ts), a word was marked isAcronym if it was either an all-uppercase run or matched the known-acronym dictionary, independently of casing:

const isAcronym =
    (lastLowerCaseIndex !== undefined && allUpper) ||
    knownAcronyms.has(word.toLowerCase() as (typeof acronyms)[number]);

The second clause matched the dictionary regardless of whether the source word was actually all-uppercase, so mixed-case input like Acme or lowercase acme was still flagged as an acronym and re-cased to ACME by the pascal acronym style.

Fix

Only treat a dictionary match as an acronym when the word was actually written in all-uppercase in the source name:

const isAcronym =
    allUpper &&
    (lastLowerCaseIndex !== undefined ||
        knownAcronyms.has(word.toLowerCase() as (typeof acronyms)[number]));

This preserves the existing behavior for genuinely all-caps input (ACME stays ACME, HTMLParser still treats HTML as an acronym) while no longer forcing mixed-case or lowercase names that happen to collide with the dictionary into all-caps.

Test coverage

• Extended test/inputs/json/priority/name-style.json (which runs for every language fixture) with a top-level-style-relevant property, "Acme": { "HTMLParser": true }, exercising the same word-splitting path across all languages.
• Added test/unit/top-level-name-capitalization.test.ts, which asserts the exact emitted TypeScript identifier for top-level names Acme, acme, ACME, and HTMLParser — this is needed because round-trip fixtures don't detect identifier casing (generated identifiers are self-consistent), so a unit test is the right complement per repo conventions.

Verification

• npm run build passes.
• Repro command now produces export interface Acme { ... } (previously ACME); also manually checked acme → Acme, ACME → ACME, HTMLParser → HTMLParser, Foobar → Foobar, foobar → Foobar.
• npx vitest run test/unit/ — all 167 unit tests pass (26 files).
• QUICKTEST=true FIXTURE=typescript script/test — all 78/78 TypeScript fixtures pass, including the updated name-style.json under every renderer-option combination (e.g. acronym-style: pascal).
• Other language fixtures are left to CI.

Fixes #2328

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195 changed lines — +195 / −0

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