Server architecture doc points at a file that no longer exists

## Page or file `docs/contribute/architecture/server.md`, the "Conversation Turns" section (around line 57). ## What is stale It says the turn queue lives here: > `turnRegistry` on the `Handler` (`internal/server/handlers/conversation_turns.go`) That file does not exist. The turn queue is now its own package, `internal/server/turnqueue`, and its callers are `internal/server/websocket/conn.go`, `internal/server/handlers/config.go`, and `internal/server/handlers/work/`. The behaviour the paragraph describes is still correct — one turn per conversation, server-scoped rather than connection-scoped, every path serialized into the same queue. Only the location is wrong, which makes the paragraph worse than useless for someone trying to read the code it describes. ## What would help Update the reference to `internal/server/turnqueue`, and check whether `turnRegistry` is still the right name for what the section calls it — the package exports its own type, so the sentence may read better in terms of that. `AGENTS.md` asks that architecture documents stay factual about current code, so this is exactly the kind of drift worth fixing. ## Verify ```bash ls internal/server/handlers/conversation_turns.go # No such file grep -rln "turnqueue" internal/server/ | grep -v _test ./make check docs ```