Support a coral-compatible backend + sidebar/tooling tidy

[pcolt]

Part of 2listic/coral-python#12

• Update CHANGELOG

Overview

Platform-side support for reintegrating the coral-python backend as a coral-compatible
backend: from the app's perspective it stays backendKind: coral; only the executable/plugin
paths differ. The coral-python side (a coral-style register/run CLI and a platform-native node
registry) is tracked in 2listic/coral-python#12. This PR covers the dealiiX-platform changes
needed to probe, render, and load that backend's graphs, plus a small unrelated sidebar tidy.

Also included, unrelated to the above: a pre-commit tooling fix. Prettier previously ran
after the commit was already created, leaving its formatting unstaged; it now runs via
lint-staged, scoped to staged files only, so the formatted result lands in the commit itself.

Summary

• feat: the Coral plugin path setting is now free-text with a Browse button, accepting a plugin
  .so path or an opaque -p value (e.g. a comma-separated module list); the local probe no
  longer requires it to be an existing file.
• feat: nodes with node_type: "primitive" render an editable literal (text, or checkbox for
  booleans) like elementary constructors; numeric validation is null-safe.
• fix: loading a graph no longer drops edges into an any-typed input (e.g. print_result);
  import validation now accepts an any target input, matching the live connection validation.
• refactor: moved Download Graph from the Project group into the renamed Import / Export group;
  it no longer requires a remote login and falls back to graph.json when no project is loaded.
• chore: removed the obsolete NOTE.md.
• docs: CHANGELOG entries + a note in docs/run-coral-local.md.

Test plan

• Local coral-python: Settings → Local / Coral, binary = coral-py, plugin = "math,string,phiflow",
  writable working dir → Save & Sync populates the sidebar, no skipped-node toasts.
• Drag primitive nodes (int/float/bool/str) → editable field shows; numeric invalid until valued; no console error.
• Load a coral-python graph with an any-typed input (e.g. print_result) → the edge into it is kept, not dropped as a type mismatch.
• Download Graph works while logged out and yields graph.json when no project is loaded.
• Stage a badly-formatted file and commit → the formatted version lands in the commit, git status is clean afterward.
• npm run check, npm run check:electron, and npm test pass.