process: user-facing WhatsNew.md changelog + done-state notify protocol

Done-state notifications now produce two synchronised outputs sharing
one text: an entry appended to docs/WhatsNew.md and the same string
sent via notify.sh. The text is written in German for the user-as-
reader who did not watch the session — no technical internals, no
iteration codes, lead with the change-in-the-project.

WhatsNew.md is the only file in the repo intentionally not in English;
the exception is documented in CLAUDE.md (Roles of docs/...) so a
future reader does not "correct" it back. Bounce-back notifications
stay Notify-only.

CLAUDE.md

@@ -181,6 +181,43 @@ and likely respond by returning to the session.
 By default, you act autonomous. The notification is the
 exception, not the rule.
 
+### Done-state notifications: WhatsNew.md
+
+When the trigger is **done-state** (autonomous work has wrapped
+up, nothing left to do for the user to react to), the procedure
+is two-step and the two outputs share one text:
+
+1. Append a new entry to `docs/WhatsNew.md` (newest at the bottom,
+   append-only — same chronological convention as `JOURNAL.md`).
+2. Send the same text via `~/.claude/notify.sh`.
+
+The text must be written for the **user-as-reader who did not
+watch me work**:
+
+- **Language: German.** This is a deliberate exception to the
+  English-only project rule, because WhatsNew is user-facing
+  communication, the same role German plays in our live chat.
+- **No technical internals.** Don't name crates, function
+  identifiers, type names, agent names, or iteration codes
+  (`ct.1.7`, `18a`, etc.). Describe the *change in the project*
+  — what is now possible, fixed, or visible — not the mechanics.
+- **No assumption of context.** The user is on his phone and has
+  not seen this session. Lead with the result; the *why* is fine
+  if it fits in one short clause.
+- **Length: Telegram-pragmatic.** No hard cap, but a few sentences,
+  not an essay. If the work covered multiple unrelated things,
+  bullet them.
+- **Tone: factual, not performative.** No celebration, no "I have
+  successfully…". Just "X geht jetzt, Y ist behoben, Z ist neu".
+
+**Bounce-backs** (asking the user for a design judgement or
+checkpoint) are *not* done-state and do **not** produce a
+WhatsNew entry — they stay as Notify-only.
+
+Format of a WhatsNew entry: a `## YYYY-MM-DD — <kurze Überschrift>`
+heading followed by the message body. The body must match the
+Notify text verbatim.
+
 ## Bug fixes — TDD, always
 
 Bug fixes are RED-first, autonomous, no orchestrator gate. See
@@ -232,6 +269,15 @@ Existing entries are not retroactively renamed.
   bite-sized executable plan produced by `skills/plan`, consumed
   by `skills/implement`.
 
+- **`docs/WhatsNew.md`** (since 2026-05-11): the user-facing
+  changelog, written in German for the user-as-reader who does
+  not watch the implementation. Entries are appended at done-state
+  notifications and mirror the Notify text verbatim. See the
+  "Done-state notifications" subsection above for the editorial
+  rules. This is the only file in the repo that is intentionally
+  not in English.
+
 Together these answer three questions: "what is the language right
 now?" (DESIGN), "how did we get here?" (JOURNAL, specs, plans),
-and "what's next?" (roadmap).
+and "what's next?" (roadmap). `WhatsNew.md` is the user-facing
+mirror of the JOURNAL — the same history, told without internals.