feat: Add Update Type/Diff to RoomInfoListener callback

Nobody has claimed this yet.

Hello, I'm writing on behalf of the Citadel product developed by ERCOM.

**Add an update type or diff field to the `RoomInfoListener` callback to enable efficient client-side updates and prevent unnecessary re-renders.**

## Description

Currently, the `RoomInfoListener` callback provides the full `RoomInfo` object whenever *any* property of the room changes.

```javascript
interface RoomInfoListener {
call(info: RoomInfo): Promise;
}
```

**The Problem:**
The client receives the entire `RoomInfo` object but has no way of knowing *what* specifically changed (e.g., did the name change? the avatar? the unread count? or just the power levels?).

To prevent unnecessary React re-renders, the client currently has to manually compare every single field against its local state:

```javascript
// Current inefficient client logic
if (newMetadata.name !== metadata.name ||
newMetadata.topic !== metadata.topic ||
newMetadata.avatar !== metadata.avatar ||
newMetadata.numUnreadMessages !== metadata.numUnreadMessages) {
// Update state...
}
```

This is inefficient because:

- **Performance:** Deep comparison of objects (especially large ones like `powerLevels` or member lists) is expensive on the main thread.
- **Complexity:** Client code becomes bloated with manual diffing logic.
- **Over subscription:** We might trigger heavy operations (like re-fetching the member list) when only a trivial field (like a typing notification or unread count) changed.

## Suggested Solution

Please enhance the `RoomInfoListener` to include an `updateType` or `changedFields` property.

### Option A: Update Type Enum

Provide a specific tag indicating the reason for the update.

```javascript
const RoomInfoUpdateType = {
Name: 'Name',
Topic: 'Topic',
Avatar: 'Avatar',
UnreadCount: 'UnreadCount',
Members: 'Members',
PowerLevels: 'PowerLevels',
...
} as const;

type RoomInfoUpdateType = typeof RoomInfoUpdateType[keyof typeof RoomInfoUpdateType];

interface RoomInfoUpdate {
info: RoomInfo;
type: RoomInfoUpdateType; // What changed?
}
```

### Option B: Changed Fields Mask

Provide a bitmask or list of fields that changed.

```javascript
interface RoomInfoUpdate {
info: RoomInfo;
changes: ["name", "numUnreadMessages"]; // Array of changed property names
}
```

## Acceptance Criteria

1. The `RoomInfoListener` callback provides context on what changed.
2. Clients can switch on the update type to selectively update only the relevant parts of their state (e.g., update unread badge without re-rendering the room header).

## Impact

- **Significant Performance Gain:** Clients can skip expensive checks (like member list diffing) when only simple metadata changes.
- **Cleaner Code:** Removes the need for manual field-by-field comparison in the UI layer.
- **Reduced Re-renders:** React components will only re-render when data they actually care about changes.
```# Add an update type or diff field to the `RoomInfoListener` callback to enable efficient client-side updates and prevent unnecessary re-renders.

Start by locating the RoomInfoListener callback and tracing where RoomInfo updates are emitted. Review how each room property change is represented and whether existing tests cover listener notifications. The work is done when callbacks expose reliable change context and clients can selectively react without manually comparing the full RoomInfo.

Written by the indexing model from the issue text.