feat: add component and style lint with biome.

[knightedcodemonkey]

No description provided.

[Copilot]

Pull request overview

Adds in-browser lint diagnostics for component + styles using Biome (WASM via CDN), and extends the diagnostics UI to represent pending state and combined diagnostics counts.

Changes:

• Introduces a Biome-backed lint diagnostics controller and wires it into the app with new “Lint” buttons for component/styles.
• Extends diagnostics UI state to track lint runs + pending status, including a pending spinner on the diagnostics toggle.
• Expands Playwright coverage for typecheck + lint diagnostics UX and updates docs with next steps / CDN guidance.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/styles/diagnostics.css	Adds pending-state spinner styling + keyframes for diagnostics toggle.
src/modules/type-diagnostics.js	Adds pending signaling + cancel API; refines status updates during typecheck.
src/modules/lint-diagnostics.js	New Biome WASM lint engine integration and normalization/formatting of diagnostics.
src/modules/diagnostics-ui.js	Tracks lint run counts + pending flags; updates toggle label/class and aria-busy.
src/modules/cdn.js	Adds CDN import spec for @biomejs/wasm-web.
src/index.html	Adds “Lint” buttons for component and styles panels.
src/app.js	Wires lint controller into UI, schedules stale re-lints, and resets diagnostics flows on mode changes.
playwright/app.spec.ts	Adds E2E coverage for typecheck/lint success, errors, and pending indicator behavior.
docs/next-steps.md	Updates roadmap items around lint rule review and CI E2E determinism.
docs/build-and-deploy.md	Adds note about centralized CDN specs (path reference needs correction).
AGENTS.md	Adds contributor guidance about centralized CDN specs (path reference needs correction).

Comments suppressed due to low confidence (1)

src/modules/diagnostics-ui.js:71

• getDiagnosticsIssueLevel only returns 'error' when getDiagnosticsIssueCount() > 0. This misses cases where a scope sets level: 'error' but provides no lines (e.g. "Type diagnostics unavailable" / "Biome unavailable"), leading to an error-styled drawer (panel-footer--error) but a neutral diagnostics toggle. Consider treating diagnosticsByScope.component.level === 'error' || diagnosticsByScope.styles.level === 'error' as an error level regardless of line count, while keeping the count for the label.

  const getDiagnosticsIssueLevel = () => {
    if (typeDiagnosticsPending || lintDiagnosticsPending || hasActiveDiagnosticsRuns()) {
      return 'pending'
    }

    if (getDiagnosticsIssueCount() > 0) {
      return 'error'
    }

    if (hasDiagnosticsOkResult()) {
      return 'ok'
    }

    return 'neutral'

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