- Fix the UI problems with our CodeMirror integration (Fixed view stability; Fixed a focus bug; Fixed errors caused by diagnostics range exceptions; Fixed linter invalidation--see https://discuss.codemirror.net/t/problem-trying-to-force-linting/5823; Implemented edit-coalescing for performance).
- Introduce an algorithm for applying text edits to an AST. Compared to the GUI1 approach, the new algorithm supports deeper identity-stability for expressions (which is important for subexpression metadata and Y.Js sync), as well as reordered-subtree identification.
- Enable the code editor.
Introduce `SourceDocument`, a reactive source code representation that can be synced from a `MutableModule`. `SourceDocument` replaces various logic for tracking source code and spans--most importantly, `ReactiveModule`. There is no longer any reactively-tracked `Module`, per-se: Changes to the `MutableModule` attached to the synchronized `ydoc` are pushed as Y.Js events to the `SourceDocument` and `GraphDb`, which are reactively tracked. This avoids a problem in the upcoming text-synchronization (next PR) that was caused by a reactive back channel bypassing the `GraphDb` and resulting in observation of inconsistent states.
Stacked on #8956. Part of #8238.
- Synchronize Y.Js clients by AST (implements #8237).
- Before committing an edit, insert any parentheses-nodes needed for the concrete syntax to reflect tree structure (fixes#8884).
- Move `externalId` and all node metadata into a Y.Map owned by each `Ast`. This allows including metadata changes in an edit, enables Y.Js merging of changes to different metadata fields, and will enable the use of Y.Js objects in metadata. (Implements #8804.)
### Important Notes
- Metadata is now set and retrieved through accessors on the `Ast` objects.
- Since some metadata edits need to take effect in real time (e.g. node dragging), new lower-overhead APIs (`commitDirect`, `skipTreeRepair`) are provided for careful use in certain cases.
- The client is now bundled as ESM.
- The build script cleans up git-untracked generated files in an outdated location, which fixes lint errors related to `src/generated` that may occur when switching branches.
