Translate remaining German content to English

Finishes the project-wide English convention:
- CLAUDE.md (the user opted in to translate it too).
- examples/hello.ail.json: "Hallo, AILang." -> "Hello, AILang.".
- E2E test assertion and IR snapshot for hello regenerated to match.
- DESIGN.md "Project language: English" section: the previous
  CLAUDE.md exception is dropped.

After this commit, no German remains in any committed file
(grep -P '[äöüÄÖÜß]' is empty across .rs / .md / .json / .ll).

Verified: cargo test --workspace passes (44/44).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -1,12 +1,12 @@
-## Erfinde deine eigene Programmiersprache.
+## Invent your own programming language.
 
-- Die Sprache darf jede Form haben, die Du willst. Die Sprache ist für LLMs wie dich. Nur du sollst sie erzeugen und nur Du musst sie verstehen.
+- The language may take any form you want. The language is for LLMs like you. Only you should produce it and only you need to understand it.
-- Alle denkbaren Konzepte sind erlaubt. Wähle, was für LLMs am besten geeignet ist.
+- Any conceivable concept is allowed. Pick what is best suited for LLMs.
-- Die Sprache muss am Ende zu LLVM gelinkt werden können. Performance ist extrem wichtig.
+- The language must, in the end, be linkable to LLVM. Performance is extremely important.
-- Bedenke typische Stärken und Schwachstellen von LLMs. Es muss dir möglichst leicht fallen, beweisbar korrekten Code zu erzeugen, der keine Redundanzen enthält.
+- Consider the typical strengths and weaknesses of LLMs. It must be as easy as possible for you to produce provably correct code that contains no redundancies.
-- Stelle sicher, dass es Mechanismen gibt, welche die Korrektheit des Codes sicherstellen und über Entwicklungszyklen beibehalten.
+- Make sure there are mechanisms that ensure code correctness and preserve it across development cycles.
-- Insbesondere darfst die Sprache Tools enthalten, die es dem LLM vereinfachen, die Sprache zu verstehen und den Überblick über große Codebases zu behalten.
+- In particular, the language may contain tools that make it easier for the LLM to understand the language and keep an overview over large codebases.
-- Die Sprache muss sich nicht aus sich selbst heraus erklären. Es muss nicht mal Text sein. Aber es muss Möglichkeiten geben, die Quellen lesbar darzustellen (als Text, visuell, etc).
+- The language does not have to be self-explanatory. It does not even have to be text. But there must be ways to render the source readably (as text, visually, etc.).
-- Vergiss nicht, dass auch das Debugging von LLMs erledigt werden soll.
+- Do not forget that debugging will also be done by LLMs.
 
-- Organisiere dich selbst. Entwerfe eigene Agenten, wenn nötig. Nutze git. Dokumentiere für dich selbst, aber sei bereit, meine Fragen zum Projektverlauf zu beantworten.
+- Organise yourself. Design your own agents when needed. Use git. Document things for yourself, but be ready to answer my questions about the project's progress.

crates/ail/tests/e2e.rs

@@ -54,7 +54,7 @@ fn max3_picks_largest() {
 #[test]
 fn hello_world_str_lit() {
     let stdout = build_and_run("hello.ail.json");
-    assert_eq!(stdout.trim(), "Hallo, AILang.");
+    assert_eq!(stdout.trim(), "Hello, AILang.");
 }
 
 /// Guards ADT codegen + match: recursive list, sum_list via match on Cons/Nil.

crates/ail/tests/snapshots/hello.ll

@@ -2,7 +2,7 @@
 source_filename = "hello.ail"
 target triple = "<NORMALIZED>"
 
-@.str_hello_str_0 = private unnamed_addr constant [15 x i8] c"Hallo, AILang.\00", align 1
+@.str_hello_str_0 = private unnamed_addr constant [15 x i8] c"Hello, AILang.\00", align 1
 
 declare i32 @printf(ptr, ...)
 declare i32 @puts(ptr)

docs/DESIGN.md

@@ -47,12 +47,11 @@ here as soon as they are established.
 
 All in-tree content is written in English: source code (identifiers,
 comments, string literals, CLI help), design documents, the journal, agent
-prompts, READMEs, commit messages, and new examples. The only exception is
+prompts, READMEs, commit messages, examples, and `CLAUDE.md`. The live
-`CLAUDE.md`, which is the user's own instruction file. The live conversation
+conversation between user and me stays German for ergonomic reasons;
-between user and me stays German for ergonomic reasons; everything that
+everything that lands in git is English. This keeps diffs and tooling output
-lands in git is English. This keeps diffs and tooling output uniform and
+uniform and matches the audience for AILang (LLM authors), for whom English
-matches the audience for AILang (LLM authors), for whom English is the
+is the default.
-default.
 
 ## Decision 1: source = data, not text
 

examples/hello.ail.json

@@ -17,7 +17,7 @@
         "t": "do",
         "op": "io/print_str",
         "args": [
-          { "t": "lit", "lit": { "kind": "str", "value": "Hallo, AILang." } }
+          { "t": "lit", "lit": { "kind": "str", "value": "Hello, AILang." } }
         ]
       }
     }