Feature: Ability to link specific prompts to modes (depends on #969)

[cstroliadavis]

Description:

I was just thinking about some of the Prompts ideas I put in last night (see #968 and #969) and it occurs to me that once these are available, it could be very useful if you could tie specific prompts to specific modes.

There could still be an option to keep some custom available for every mode (Meta Prompt, for instance).

Reason:

It seems like when I'm in a particular mode, there are typically certain things I'm doing and if I could put various prompts into that mode that are specific to that type of work that don't show up in other modes, it could really help save me time and energy and increase the chance that I would use those saved prompts once there get to be a lot.

Example:

Once again, I don't have a visual for you, but once we have the editor for Custom Prompts available, I could see being able to put some sort of checklist (similar to the one we use for tool selection in modes) somewhere into the editor for the custom prompts. It could have an "all modes" checkbox that would disable/hide the others, but if unchecked, a list of all existing modes would appear and the user could select which modes the Custom Prompt applies to.