docs(sprints): add protocol v7 bump requirement to client briefing

Server PR #23 bumped PROTOCOL_VERSION to 7 (pending_recognitions field).
Client must match before #431 fog entity visualization or joint testing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/sprints/sprint-7/client.md

@@ -237,6 +237,15 @@ Use `db/connectors/ticket show <id>` for full details.
 - Response options are buttons/selectable text, not just labels
 - Auto-pause integration: future sprint (single-player pause when dialogue active)
 
+## Protocol Version Bump (REQUIRED)
+
+Server PR #23 bumped `PROTOCOL_VERSION` from 6 to 7 (new `pending_recognitions` field in `ObserverSnapshot`). The client **must** update to match before the next joint test.
+
+**File:** `client/scripts/protocol/protocol.gd:14`
+**Change:** `const PROTOCOL_VERSION: int = 6` → `const PROTOCOL_VERSION: int = 7`
+
+This is a prerequisite for #431 (fog entity visualization), which reads `pending_recognitions` to render cognitive delay grey blobs. Without the bump, the client will reject server handshakes or silently corrupt snapshot data.
+
 ## Dependency Chain
 
 ```
@@ -252,6 +261,9 @@ Parallel standalone:
 
 Server dependency:
 #423 (server cognitive delay) → #431 (fog entity viz)
+
+Protocol sync (REQUIRED before joint test):
+Protocol v7 bump → #431 (fog entity viz)
 ```
 
 ## Sprint 7 Client Load