Summary character length should be enforced

[flaki]

Currently the character length limit of the CFP summary is stated, but not enforced, and it should be.

It should probably also be configurable.

[flaki]

One difficulty of this is currently fields used by the form (and constraints such as whether they are required) are stored on the backend in a hardcoded structure. We should make this configurable via the UI. Either way, we will need to figure out how to encode these constraints into the structure. One idea is:

  *language
   presentation_lang
  *presentation_format
  *title
  *summary(maxlen:240)
  *description
  ...

In the above case we add (maxlen:240) after the property name, which is a simple list of key-value pairs that could then be interpreted as constraints by the clientside CFP App, as well as the backend verification.

(Note: in the structure the *-s represent the required fields)

[flaki]

Since version cfp-app 1.1.4 we warn about exceeding the Summary field length, but this is a one-off hardcoded check (and for now we do not enforce the length limitation on either the client or serverside).