`intlayer fill` does not re-translate keys whose source value changed

Problem

When using intlayer fill to auto-fill all locales, editing the value of an existing key in the source locale has no effect on the other locales: the old translations are kept.

// before
title: t({ en: 'Welcome', fr: 'Bienvenue', es: 'Bienvenido' })

// after editing en and running `npx intlayer fill`
title: t({ en: 'Welcome back', fr: 'Bienvenue', es: 'Bienvenido' }) // fr / es untouched

Nothing in the configuration allows changing this behavior.

Why

fill in its default complete mode has no change detection. It only compares the source-locale content with each target locale and keeps the keys that are missing in the target. A key that already has a value is considered done, whatever the source now says.

Current workarounds

• Rename the key (it becomes "missing" everywhere and gets re-translated).
• Delete the stale translations by hand.
• npx intlayer fill --mode review --key <dictionary-key> — review mode re-translates every key of the dictionary, including the up-to-date ones (cost + risk of unwanted changes on unrelated keys).

What we'd like

fill should detect that the source value of an existing key changed since it was last translated, and re-translate that key (only that key) in the target locales.

Constraints to keep in mind

• .intlayer/ is git-ignored, so nothing persisted there survives a fresh clone or CI.
• git may not be installed (or the project may not be a repo), so a git diff-based detection can't be the only mechanism.
• Detection should work for every content declaration format (.content.ts, .json, .md, per-locale JSON via the sync plugins, …), i.e. ideally on the built dictionaries rather than on the raw files.

Possible directions

1. Journal / lock file — persist a hash of the source value each translation was made from (e.g. a committed intlayer.journal.json keyed by dictionary key → node path → target locale). On the next fill, a mismatching hash means the key is stale and gets re-translated. First run seeds the file without re-translating anything.
2. Git-based (when available) — diff the source-locale values of .content.* files against the last commit / a given ref (--git-diff, --base options already exist on some commands) and run fill --mode review --key <changed-keys> on the affected dictionaries. Cheap to build on top of existing flags, but not usable without git.
3. Content similarity — the doc review command already compares paragraph similarity across languages for docs; the same idea is hard to apply reliably to short UI strings, so probably not the way to go on its own.

A combination is plausible: journal as the source of truth, with a git-based shortcut to select the dictionaries to check.

Related

• intlayer fill --mode review (re-translates everything)
• intlayer doc review (similarity-based review for docs)

Start at the intlayer fill command and its complete and review modes; inspect how built dictionaries are produced for .content.ts, .json, .md, and per-locale JSON through sync plugins. Compare the existing doc review similarity flow and any --git-diff/--base handling. Done means changed source values are detected without relying only on git and only affected target keys are re-translated.