Align cn1playground light/dark theming with design guide tokens

[liannacasper]

Motivation

• Bring the CN1 playground UI into alignment with the project’s design language so both light and dark modes use the same semantic color tokens, contrast, and interaction rules.
• Ensure the embedded Monaco editor shares the same palette and selection/cursor semantics as the surrounding playground surfaces.

Description

• Reworked the playground stylesheet scripts/cn1playground/common/src/main/css/theme.css to use the design-guide color tokens and navy-based dark palette across panels, inspector controls, tabs, and previews.
• Updated the editor host scripts/cn1playground/src/html/playground-editor/index.html to match the design palette, typography stack, border and inline message colors for both light and dark modes.
• Added dedicated Monaco themes in scripts/cn1playground/src/html/playground-editor/editor.js (cn1-playground-light and cn1-playground-dark) and wired applyTheme() to use them so editor background/foreground/cursor/selection colors follow the design language.

Testing

• Ran node --check scripts/cn1playground/src/html/playground-editor/editor.js which succeeded.
• Ran git diff --check which reported no whitespace/issues.
• Ran the playground smoke script bash ./scripts/cn1playground/tools/run-playground-smoke-tests.sh and it failed during the Maven build due to an unresolved local artifact (com.codenameone.playground:cn1playground-ZipSupport:jar:common:1.0-SNAPSHOT), so the full Maven build could not complete in this environment.

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Codex Task

[github-actions]

Cloudflare Preview

• URL: https://pr-4754-website-preview.codenameone.pages.dev
• Branch: pr-4754-website-preview