fix(typescript-input): strip brace-wrapped types from JSDoc @type tags

[schani]

Bug

TypeScript input properties documented with a JSDoc @type {...} tag (e.g.
@type {string}) produced invalid "type": "{string}" in the generated
JSON Schema instead of "type": "string", when converting via
--src-lang typescript --lang schema.

export type Person = {
  /**
   * @type {string}
   */
  name: string;
}

produced:

{ "type": "{string}", "title": "name" }

instead of the expected:

{ "type": "string", "title": "name" }

Because the resulting schema is invalid JSON Schema, feeding it back into
quicktype for any other target language then failed hard with
Invalid type {string} in JSON Schema.

Root cause

packages/quicktype-typescript-input wraps the typescript-json-schema npm
package (a normal, unforked dependency). That package hardcodes type as an
always-on "validation keyword": when it sees a JSDoc @type {TypeExpression}
tag on a symbol, it copies the tag's raw text — including the surrounding
braces from the JSDoc syntax — verbatim into the generated schema's type
field, overwriting the correct type inferred from the TypeScript type. This
behavior isn't configurable via the settings quicktype passes in, so it can't
be disabled at the call site.

Fix

Added a small post-processing pass (sanitizeTypeAnnotations) in
packages/quicktype-typescript-input/src/index.ts, run on the schema
right after generateSchema() returns (in the same spirit as the existing
post-processing already done in that function). It walks the schema
recursively and strips a single pair of surrounding braces from any string
type value, e.g. turning "{string}" into "string".

Test coverage

Added a regression test in test/unit/typescript-input.test.ts reproducing
the issue's exact TypeScript input (a @type {string}-documented property
plus a Required<Person> usage) and asserting the generated schema's
property type is the plain string "string". The test was confirmed to fail
on unfixed code (Received: "{string}") before the fix was applied.

Verification

• npm run build — passes
• npm run test:unit — 25 files, 164 tests pass (including the new
  regression test)
• Manually re-ran the issue's repro:
  node dist/index.js --src person.ts --src-lang typescript --lang schema
  now emits "type": "string" instead of "type": "{string}"
• Manually confirmed the cascading failure is also fixed: generating Go
  output from the same TypeScript input (--lang go) now succeeds instead
  of erroring with Invalid type {string} in JSON Schema
• This bug is on the TypeScript-as-input-language path, which isn't
  exercised by the JSON/JSON-Schema fixture system (that operates on
  JSON/JSON-Schema inputs, not TypeScript source), so unit test coverage
  in test/unit/ is the appropriate mechanism here, consistent with how the
  rest of that file already tests schemaForTypeScriptSources. CI will run
  the full fixture and unit test suites.

Fixes #2695

🤖 Generated with Claude Code