Add validation for deprecated design tokens

[mrleemurray]

This pull request updates the design token validation logic to align with the latest naming conventions and adds a new check for deprecated token usage. The most significant changes are the renaming of several font size and weight tokens to their new generic forms, and the introduction of a linter that detects and reports deprecated tokens, suggesting their replacements. The summary reporting at the end of the stylelint run now also includes a count of deprecated token findings.

Design token naming updates:

• Updated font size and weight token suggestions in validateDesignTokens.ts to use the new --vscode-fontSize-* and --vscode-fontWeight-* variables instead of the old --vscode-agents-* and --vscode-bodyFontSize* variables. This affects the mapping, comments, and violation messages. [1] [2] [3] [4] [5]

Deprecated token detection:

• Added a new function validateDeprecatedTokens in validateDesignTokens.ts that scans for usages of deprecated design tokens and reports them with suggested replacements.
• Integrated validateDeprecatedTokens into the stylelint pipeline in build/stylelint.ts, so deprecated token usage is now detected and reported during linting. [1] [2]

Reporting improvements:

• Added a new deprecated category to the design token summary counts and included it in the final summary output. [1] [2] [3]

[Copilot]

Pull request overview

This PR extends the build-time stylelint design-token validation with a new check that flags usage of deprecated --vscode-bodyFontSize* tokens and suggests their current replacements. It wires the new validateDeprecatedTokens validator into the gulp stylelint task (including its own summary tally/footer category), and it retargets the existing font-size and font-weight suggestions from the agents--prefixed ramp to the generic --vscode-fontSize-* / --vscode-fontWeight-* ramp, updating the accompanying comments accordingly.

The deprecation mapping is correct and matches the @deprecated annotations in src/vs/platform/theme/common/sizes/baseSizes.ts and the design-tokens instructions doc. The one point worth a human decision: these validators run by default on src/vs/sessions/**, where the surrounding CSS and the sessions ramp table in design-tokens.instructions.md use the agents--prefixed variants, so switching the ramp/weight suggestions to the generic tokens introduces a convention inconsistency in that area.

Changes:

• Add validateDeprecatedTokens to detect deprecated --vscode-bodyFontSize* vars and suggest replacements, with prefix-boundary handling to avoid double-reporting.
• Integrate the new validator into build/stylelint.ts (findings collection, deprecated count category, and footer summary).
• Retarget FONT_SIZE_RAMP and the font-weight suggestion from --vscode-agents-fontSize-*/--vscode-agents-fontWeight-* to the generic --vscode-fontSize-*/--vscode-fontWeight-* tokens (plus comment wording updates).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
build/lib/stylelint/validateDesignTokens.ts	Adds the validateDeprecatedTokens validator and deprecated-token map; retargets font-size/weight suggestions to generic tokens and refreshes comments.
build/stylelint.ts	Imports and runs the new validator, adds the deprecated category to the tally, total, and summary footer.