feat: add report-audit-token-usage MCP tool

[poltorak]

New tool for auditing design token health in consumer style files. Two modes — validate (typo detection with suggestions) and overrides (token re-declaration detection).

Validate mode

• Checks var() references against the loaded token dataset
• Suggests corrections for invalid tokens using Levenshtein distance (threshold ≤ 3)
• Supports multiple token prefixes — derives all distinct prefixes (--semantic-, --ds-, etc.) from the dataset automatically when propertyPrefix is null
• Optional brand-specific warnings for tokens not available in all brands

Overrides mode

• Detects token re-declarations via :host, ::ng-deep, class selectors, :root[data-theme]
• Detects !important on token-consuming declarations
• Works without token data (detection-only / zero-config mode)
• Optional classification when token dataset is available: legitimate, component-override, deep-override, important-override, inline-override, scope-violation

Supporting changes

• styles-ast-utils: ScssPropertyEntry now exposes important: boolean from PostCSS (PostCSS strips !important from decl.value into decl.important)
• glob-utils: new tests for glob-to-regex conversion
• token-dataset-loader: minor adjustments for token loading
• docs: added tool entry in tools.md, clarified propertyPrefix behaviour in architecture-internal-design.md

Files added

Path	Purpose
audit-token-usage.tool.ts	Main handler, formatter, prefix derivation, persistence
models/schema.ts	MCP tool schema definition
models/types.ts	Input/output type definitions
utils/validate-mode.ts	Validate pipeline — var() extraction, prefix matching, typo suggestions
utils/overrides-mode.ts	Overrides pipeline — declaration/consumption scanning
utils/override-classifier.ts	Mechanism detection and override classification
utils/edit-distance.ts	Levenshtein distance (Wagner-Fischer, O(min(m,n)) space)
index.ts	Public API exports

Test coverage

• audit-token-usage.tool.spec.ts — output structure, summary counts, formatter
• graceful-degradation.spec.ts — missing config, empty dataset, detection-only mode
• edit-distance.spec.ts — identity, symmetry, empty string, known distances
• overrides-mode.spec.ts — mechanism detection, classification, runOverridesMode pipeline
• validate-mode.spec.ts — prefix filtering, suggestion threshold, invalid token report fields