Transparency of chat bubble needs customization

**Motivation**

The chat bubble (where you enter new chat) having transparency without customization can lead to illegible moments when you scroll back to respond to something you have overlapping text.

**Proposed solution**
option to disable or set transparency of the chat bubble, likely by default should be more opaque.

**Alternatives considered**
I favored being able to read what I was typing only, sorry.

**Additional context**
Linux, tried various themes, not sure if some have this disabled and others not, but the setting should be independent or just disabled.

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no dupes found

No file or test is named in the issue. Start by locating the chat bubble UI entry point and checking how theme-related settings are handled on Linux. Done means the bubble’s transparency can be disabled or adjusted independently, with a more opaque default and behavior that remains readable while scrolling.

Written by the indexing model from the issue text.