Adopt date-prefixed ADR filenames

docs/agents/domain.md

@@ -18,11 +18,16 @@ Single-context repo (most repos):
 /
 ├── CONTEXT.md
 ├── docs/adr/
-│   ├── 0001-event-sourced-orders.md
-│   └── 0002-postgres-for-write-model.md
+│   ├── 20260612-event-sourced-orders.md
+│   └── 20260704-postgres-for-write-model.md
 └── src/
 ```
 
+ADR files are named `YYYYMMDD-kebab-title.md`, where the date is when the
+decision was accepted. The date prefix keeps them sortable chronologically and
+avoids the renumbering churn that sequential IDs cause when two branches add an
+ADR at once. Refer to an ADR by its slug, e.g. ADR `event-sourced-orders`.
+
 ## Use the glossary's vocabulary
 
 When your output names a domain concept (in an issue title, a refactor proposal, a hypothesis, a test name), use the term as defined in `CONTEXT.md`. Don't drift to synonyms the glossary explicitly avoids.
@@ -33,4 +38,4 @@ If the concept you need isn't in the glossary yet, that's a signal — either yo
 
 If your output contradicts an existing ADR, surface it explicitly rather than silently overriding:
 
-> _Contradicts ADR-0007 (event-sourced orders) — but worth reopening because…_
+> _Contradicts ADR `event-sourced-orders` — but worth reopening because…_