Assistant: Implement a first web prototype of the assistant

As the required design and content is ready we can start implementing a first web prototype of the router. This doesn’t require all previous decisions to be made to start implementing bits of it.

Parent Task: #8580 (closed)

Subtasks

#9312 (closed)
#9313 (closed)
#9210 (closed)
#9206 (closed)

Related issues

Blocks #8589 (closed)
Blocked by #8588 (closed)

Original created by @sajolida on 9310 (Redmine)

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