Lohnt sich dein eigenes Loco?

Build a local translation management app called Strings. No accounts, no cloud, no telemetry.

Stack, non negotiable:
- Node 20 with Express and TypeScript
- SQLite via better-sqlite3, file at ./data/strings.db
- Server rendered EJS templates plus a little vanilla JS, no React, no bundler
- Runs with `npm run dev` on localhost:4321

Data model:
- projects: id, name, source_locale
- locales: id, project_id, code (BCP 47)
- keys: id, project_id, name (dot notation allowed), context note, created_at
- translations: key_id, locale_id, plural_category (one of other, one, two, few, many, zero), value, updated_at
- history: translation_id, old_value, new_value, changed_at

UI:
- Project list, then a grid page per project: rows are keys, columns are locales, cells are inline editable textareas that save on blur via fetch
- Filters: untranslated only, search by key or value substring
- Per key detail drawer showing context note, plural forms, and history
- Progress bar per locale showing percent of keys with a non empty value

Import and export, implement exactly these three formats and be strict:
- Flat and nested JSON
- gettext PO, including Plural-Forms header parsing and msgid_plural
- Android strings.xml, including plurals blocks with quantity attributes
Use the CLDR plural categories for each locale code; hardcode a small lookup table for the twenty most common locales and fall back to other plus one.

Also ship a CLI: `npm run export -- --project=X --locale=fr --format=po --out=./out` so a build script can use it.

Optional machine translation: if DEEPL_API_KEY is set in .env, add a "fill empty cells" button per locale that batches untranslated source strings through DeepL and marks results as machine translated with a flag shown in the grid. If the key is missing, hide the button rather than erroring.

Out of scope: multi user auth, sharing links, webhooks, screenshots, glossary, TMX.

Include a README with setup, a `.env.example`, and seed data for one project with English, French and Polish so plural handling is exercised on day one.