feat(session): snapshot getters for IgnoredUsersManager + GroupInformationManager

Extends the v2.1.0 React-friendly snapshot pattern (originally on
SessionDataManager / RoomSessionManager) to two more session-state
holders the React client reads frequently:

- IgnoredUsersManager.getIgnoredUsersSnapshot(): ReadonlyArray<string>
- GroupInformationManager.getGroupBadgesSnapshot(): ReadonlyMap<number, string>

Both follow the same shape: lazy-frozen snapshot, cached until the
underlying state mutates, then invalidated and a dispatched event lets
the React client rebuild via useSyncExternalStore.

Two new NitroEventType members carry the invalidation signal:
- IGNORED_USERS_UPDATED — dispatched by IgnoredUsersManager whenever
  the list changes (initial load, add, remove, queue-truncate case 2).
- GROUP_BADGES_UPDATED — dispatched by GroupInformationManager only
  when the incoming HabboGroupBadges payload contains at least one
  new or changed mapping (no-op refresh stays quiet).

This lets the user-info popup, profile page, friend/guild filtering,
and any other consumer share a single read through useSyncExternalStore
instead of each subscribing to the underlying message events
independently.

API additions are interface-respecting and backwards-compatible — the
existing `isIgnored(name)` / `getGroupBadge(groupId)` accessors stay
untouched.

packages/api/src/nitro/session/IGroupInformationManager.ts

@@ -2,4 +2,13 @@ export interface IGroupInformationManager
 {
     init(): void;
     getGroupBadge(groupId: number): string;
+
+    /**
+     * Returns the current `groupId -> badgeId` map as a frozen,
+     * referentially stable ReadonlyMap. The same reference is returned
+     * across reads until the underlying badges change; mutations
+     * dispatch `NitroEventType.GROUP_BADGES_UPDATED` to signal
+     * invalidation.
+     */
+    getGroupBadgesSnapshot(): ReadonlyMap<number, string>;
 }

packages/api/src/nitro/session/IIgnoredUsersManager.ts

@@ -6,4 +6,14 @@ export interface IIgnoredUsersManager
     ignoreUser(name: string): void;
     unignoreUser(name: string): void;
     isIgnored(name: string): boolean;
+
+    /**
+     * Returns the current ignored-users list as a frozen, referentially
+     * stable array. The same reference is returned across reads until
+     * the list is mutated; mutations dispatch
+     * `NitroEventType.IGNORED_USERS_UPDATED` to signal invalidation.
+     *
+     * Pairs with `useSyncExternalStore` on the React client.
+     */
+    getIgnoredUsersSnapshot(): ReadonlyArray<string>;
 }