Pipeline/state

[retailcoder]

Objectives:

• Get editor/client to communicate with language server on change/open/closed/etc.
• Get syntax errors and diagnostics to appear as text markers (/squiggles)
• Get markers to render an actionable icon/menu ("ducky button") in a dedicated marker margin
• Get document diagnostics and foldings to refresh correctly
• Adjust idle timer default, make configurable

[retailcoder]

Doesn't quite refresh correctly, but there's back-and-forth going on between the editor and the server when a code document is modified, and that's what I wanted to see at this stage.

Margin displays an appropriate icon for diagnostics, but icon isn't actionable. Text markers clear correctly on change, but not the icons in the margin, and foldings do not seem to load consistently - possible race condition in state assignment.