docs: update documentation to OKF v0.1 format

docs/guides/challenges-board.md

@@ -28,7 +28,14 @@ The first time the page mounts it triggers `ChallengesStore.load()`
 which calls `GET /api/v1/challenges/board`. It also calls
 `GET /api/v1/challenges/status` once to populate the event state
 synchronously, then opens the authenticated SSE stream on
-`/api/v1/events` for live `solve` frames.
+`/api/v1/events` for live `solve` frames`.
+
+The mount order is significant: `ChallengesPage.ngOnInit()` calls
+`store.setMyUserId(user?.id ?? null)` **before** `store.load()`. If the
+singleton's cache belongs to an unknown or different user, `setMyUserId`
+calls `reset()` first so the new board is never blended with a previous
+user's `solvedByMe`. See
+[Per-User `solvedByMe` Across the Session Boundary](/guides/challenges-per-user-state.md).
 
 # How to access (tester steps)
 
@@ -209,4 +216,5 @@ destruction of the page the SSE source is closed via
 - [System Endpoints](/api/system.md) (legacy `/events/status`)
 - [Scoreboard Stream](/guides/scoreboard-stream.md)
 - [Authenticated Shell](/guides/authenticated-shell.md) (SSE transport)
+- [Per-User `solvedByMe` Across the Session Boundary](/guides/challenges-per-user-state.md) (logout/login, peer-tab, SSE-unauthorized reset)
 - [Notifications](/guides/notifications.md) (error interceptor + service)