docs(node): document that sync config readers require initializeGT

[moss-bryophyta]

Problem

Four gt-node reference pages describe synchronous configuration readers without mentioning that they throw when called before initializeGT. initialize-gt.mdx already documents this precondition, but names only the translation functions (withGT, getGT, getMessages), so these four look exempt.

get-version-id.mdx had the sharper problem: it stated getVersionId "returns undefined when no version ID is configured." That is true only after initialization. Before it, the call throws — so a reader following the documented ?? null example on a cold path gets an exception instead of a null.

Verification

Runtime-checked against installed gt-node@1.0.15 (current published version), not the changelog:

getVersionId     -> THROWS: Cannot read I18nCache before it has been initialized
getDefaultLocale -> THROWS: Cannot read I18nConfig before it has been initialized
getLocales       -> THROWS: Cannot read I18nConfig before it has been initialized
getRequestLocale -> THROWS: Cannot read I18nConfig before it has been initialized

And after initializeGT({ defaultLocale: 'en', locales: ['en','fr'] }) with no version ID set:

getVersionId() -> undefined

So the documented string | undefined return is correct, and the missing piece is the precondition.

getLocale is intentionally not changed — it throws for a different reason (the request-scoped condition store) and its page already documents the withGT scope requirement accurately.

Changes

• Added a Requires initialization bullet to get-default-locale, get-locales, get-request-locale, and get-version-id, matching the existing house phrasing in with-gt.mdx ("must be called before X is used, or an error is thrown").
• Reworded get-request-locale's note, which softened a hard throw into "so it knows which locales are supported."
• Scoped get-version-id's undefined claim to post-initialization.
• Extended the initialize-gt.mdx note to name the four readers.

Checks

All 5 validators pass: unsafe-html 450, callouts 450, reference-links 404/256 aliases, structure valid, links all valid.

Found during a routine audit of the node docs against the published package.