Expand cSpell coverage to more file types

[julien-deramond]

Description

Backport of 565eee6

[Copilot]

Pull request overview

This PR expands spellchecking coverage (cSpell) across additional file types in the repository, adds a local npm run spellcheck entrypoint, and updates the dictionary/config to accommodate the broader scan surface.

Changes:

• Add a spellcheck npm script and include cspell as a dev dependency.
• Expand the GitHub Actions cspell workflow to scan additional file types (and .gitignore).
• Update .cspell.json words/ignore settings to reduce false positives and exclude noisy paths.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 1 comment.

File	Description
package.json	Adds cspell devDependency and a spellcheck npm script targeting more file types.
package-lock.json	Updates lockfile to include cspell and its transitive dependencies.
.github/workflows/cspell.yml	Expands the workflow’s scanned file globs (includes .gitignore and more extensions).
.cspell.json	Extends dictionary/ignore settings to support the expanded scan scope.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 4 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

.cspell.json:175

• ignoreRegExpList entry looks like an invalid Unicode escape: \u001[Bb] will be interpreted by the RegExp parser as a malformed \u escape (it expects 4 hex digits), which can cause cspell to error when loading the config. If the intent is to ignore ANSI color sequences (ESC + [...m), use \u001b and escape the literal [ properly.

  "ignoreRegExpList": [
    "\\u001[Bb]\\[[0-9;]*m"
  ],