Add Pinned-Messages Button To Room Header & Alter Pinned-Message-Banner Use

### Your use case

#### What would you like to do?
1.Move access to pinned messages into the Room header.

2. Reassign the pinned-message(s) banner for more active notifications:
- Display newly pinned messages temporarily or for a configurable period.
- Automatically pin Active Polls.

#### Why would you like to do it?
> Let Newly pinned messages show temporarily or for set period.
- Once several pinned messages accumulate in the banner (e.g. 3–5+), navigating between them becomes inefficient, often forcing users to open the side panel instead.
- Limiting how long pinned messages remain in the banner prevents it from becoming overcrowded and preserves its usefulness as a navigation aid.

- Not all pinned messages are equally important.
Newly pinned messages can be shown in the banner temporarily and dismissed after they have been viewed.
Some messages that may be more important can be set with a timer or until removed by the user.
This again keeps navigation with the banner useful and its contents relevant.

### Have you considered any alternatives?

_No response_

### Additional context

The banner should be reserved for information that becomes less valuable over time or needs a response.

The issue names no files, tests, or entry points to start from. Clarify the room-header control, banner lifetime and dismissal rules, configurable timers, and automatic active-poll pinning; done should cover the agreed behavior for each of these cases.

Written by the indexing model from the issue text.