Scrappy version of feature flags for gui

[jsibbison-square]

Enables us to merge in code that we want more user testing on without enabling it for everyone.

Adds a new menu option for Feature flags. After changing a feature flag you need to open a new chat window to see the effects.

Includes two examples feature flags:

• Changing the splash 'what goose can do?' text
• Changing the default tool output rendering between show by default or hide by default

Requires local storage to work atm. Over time should migrate to something more standard like https://openfeature.dev/ .

[michaelneale]

hrm - this seems a lot like a preferences screen vs flags (which are normally remotely controlled/optioned?)

I was thinking there could be an all on or all of thing from the file/window menu (something in main.ts) vs a seperate screen for preferences? (but interested what others think).

[jsibbison-square]

Closing this out pending future use cases.