Storyboard 2.0

The storyboard is the central UI element for the central use case of eCamp. However, it has historically evolved to the current form from paper versions over the eCamp v2 version to the current eCamp v3 version, without really questioning and gathering the choices and requirements. This issue is for gathering ideas and possibly create a concept for a new, improved storyboard content node. Once we have a clearer picture, we can create a concept for implementation and migration.

## Ideas for improvement

- [ ] The storyboard has 3 fixed columns right now, which currently waste space in many programmes.
- [ ] The time column does not "understand" the times entered. It could (optionally?) parse the time values and automatically format them in the UI and PDF in more intelligent ways. Complexity comes with custom time values and with activities with multiple schedule entries.
- [ ] The responsibles column is a plain text field too. I currently have no way to filter activities for finding all activities in which I am mentioned in the responsibles column. Making this filterable could help people find activities in which they do not have the lead, but need to prepare some part of the programme (feedback from Daniel Hermann via E-Mail) See also #5511 and #437
- [ ] In some cases, the responsibles column is used for required materials instead of people. We could offer the option for a dedicated material column.
- [ ] Comments could be anchored to individual storyboard sections or even to [a range in the rich text content](https://github.com/PfadiMH/ecampv4/commit/478c9cdce94a97490257381dfb80e8912b22d0e5).
- [ ] Editing the storyboard involves a lot of switching between mouse and keyboard (or using Tab and Enter, which interrupt the normal editing flow). However, a storyboard from the user perspective is essentially a continuous document, not a drag-and-droppable list of sections. We could use a single TipTap editor for the whole storyboard, implement the time column etc. as custom [tiptap extensions](https://tiptap.dev/docs/editor/core-concepts/introduction) which anchor the time to the start of a paragraph, and then serialize this one document into the sections structure which we store in the API. This way, using the storyboard could feel more like the piece of paper that people use outside of eCamp to plan activities.

Start by reviewing the current storyboard experience and the improvement ideas in this issue, including references to #5511, #437, and the TipTap extension documentation. Gather the requirements and compare the proposed editing, filtering, timing, comments, and materials options. Done means an agreed storyboard concept with an implementation and migration plan.

Written by the indexing model from the issue text.