feat(grida_editor): introduce the rust-native editor crate

[softmarshmallow]

Introduces crates/grida_editor — the Rust-native Grida editor: document working copy, invertible mutations, history, interaction — all editor plumbing — built from scratch as the reference implementation of the universal canvas spec, on the read-only grida engine.

See crates/grida_editor/README.md — it's doctrine, not documentation.

Why this crate exists

The legacy model was "replace the DOM with a wasm canvas, keep the JS core." @grida/canvas-wasm was a stateless renderer; JS owned all scene state and flushed it across. It worked — until it didn't. It died of split ownership (state in JS, capability in Rust — the text editor), sync-as-architecture (mutate → sync → query → update was the architecture), a write path bolted on late, and death by accretion. The failure was architectural, not incidental.

This crate answers that with six laws that are the merge bar (README §2): one owner per concern · data flows one way · the write path is first-class · one module/one concept/one golden contract · "it works" is not an argument · prototypes retire, specs carry.

What's in the box

An island: depends on grida + math2 only, nothing depends on it; the core is feature-free and rendererless (ARCH-1), the windowed shell sits behind the shell feature. Each shipped concept is specced (RFC id) → implemented → conformance-tested.

• Core — document + closed mutation vocabulary (invertible/serializable/atomic/validated), editor, history, sync (loopback CRDT), damage-ledger frame orchestration.
• Interaction — surface, HUD (intent-in / mirror-out), tool + pen/vector-edit state machine, snap family, measurement, ruler + guides, pixel grid, transparency grid, translate.
• Input — the normative keybinding sheet as data, routing, traversal, nudge.
• Structure / features — align & distribute, flatten, grouping (partial), io + wire codec, context menu (menu-as-data + anchored presenter).
• Panels & UI — the UI kernel/policy seam, widget atoms + composites (select, segmented, toggle, text, number, slider, swatch, color picker, quad, list section), the properties inspector, the hierarchy tree.
• Shell — windowed app: canvas + panels, key routing through the binding table.

Suite: 396 tests green (core) / 406 under --features shell, across 26 contract suites plus a shell-gated raster suite. Every contract test cites its RFC id (harness.md); the per-concept status ledger and remaining gaps live in crates/grida_editor/TODO.md.

Status

Spec container and pioneer (README §5). The RFC cluster under crates/grida_editor/docs is normative; this crate is its executable form. It is not a product yet — the UI is deliberately crude, the engine is read-only from here — and wasm shipping stays frozen until this rebuild can swap in as v2. Milestones M1–M4 (core → canvas → panels → the two-instance concurrent-authoring deliverable) are tracked in the TODO.

Recent work included here

The Fills properties section landed as part of this branch: the general fills paint-list domain (multiple fills; solid / gradient / image), replacing the old single-fill_solid special case — document patch domain (invertible/serializable/validated) → Binding::entry addressing + bind-owned list resolvers (ARCH-3) → paint rows assembled from atoms → tests/paint_contracts.rs. Strokes are the next slice reusing the same machinery.

Running & testing

cargo run  -p grida_editor --features shell   # the windowed shell
cargo test -p grida_editor                    # core conformance (headless, no renderer)
cargo test -p grida_editor --features shell   # full suite incl. raster probes

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Draft: large introductory diff (~50k lines, the crate authored fast and not yet fully reviewed — README §3 treats its own code as the first suspect). Opened to continue across machines.

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Project	Deployment	Actions	Updated (UTC)
backgrounds	Building	Preview, Comment	Jul 5, 2026 7:52am
blog	Building	Preview, Comment	Jul 5, 2026 7:52am
docs	Ready	Preview, Comment	Jul 5, 2026 7:52am
grida	Building	Preview, Comment	Jul 5, 2026 7:52am
viewer	Building	Preview, Comment	Jul 5, 2026 7:52am

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
code	Ignored		Jul 5, 2026 7:52am

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[softmarshmallow]

Superseded by #946 — branch renamed feat/grida-editor-paints → feat/grida-editor (the rename closed this one).