Allow to assign key/value properties to trees, nodes and segments

[philippotto]

Roadmap

• add metadata to trees and segments
• add metadata to nodes
• also allow boolean values

Detailed Description

Custom properties (key-value pairs) can be useful as metadata for skeleton trees, nodes and segments. As a first iteration, we should implement this for segments. Afterwards, for trees and then later maybe for nodes, too.

• keys should be arbitrary (but suggesting keys that were used somewhere else would be cool)
• key-values for one object are expected to be not that many (< 20 ?). sending all key-values for one object when updating them should be okay.
• an index for faster querying is not necessary for now (can be added later)
• tags should be versioned like the rest of the annotation
• UI:
  • an object that has assigned tags should have a tag icon in its list
  • for editing tags, the first iteration could look somewhat like in the screenshot below. antd tags next to each other might be nice, too, though (could be in key=value format)
  • by default, the tag UI should not swallow huge real estate
  • the active object (e.g., the active segment) could display its tags

• NML: maybe something like <property name="myPropertyName" value="x"> inside of the <segment> tag?

Context

https://scm.slack.com/archives/C5AKLAV0B/p1701863377470609

It might make sense to separately maintain a flat list of all used keys, so that autocomplete/dropdown can be offered

[philippotto]

@fm3 @normanrz I tried to jot down the details of what we discussed. feel free to extend the description.

[MichaelBuessemeyer]

@fm3 Should we reopen this because metadata for nodes is still a TODO?