Brummel
7577ab8a90
Make English the project-wide language: all comments, string literals, CLI help text, design docs, journal, agent prompts, and README. Only CLAUDE.md (the user's own instruction file) stays German, and the live conversation between user and Claude continues in German. Adds a new "Project language: English" section to docs/DESIGN.md as the durable convention. No logic changes — translation only. Four internal error strings in the typechecker were retranslated; no test asserts on their wording. Verified: cargo test --workspace passes (44/44). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>