feat(prompt-optimization): implement multi-objective evaluation metrics

Established a Pareto-ready evaluation foundation for the Genetic-Pareto (GEPA)
optimizer, supporting simultaneous optimization of accuracy and density.

Key improvements:
- Core Architecture: Defined standardized `MetricResult` and `OptimizationDirection`
  types in `packages/core/src/evals/types.ts` to support multi-objective fitness.
- Centralized Config: Implemented `packages/core/src/evals/config.ts` with tunable
  weights and detailed documentation for scoring gradients.
- Tool Alignment Metric: Created `metrics/toolAlignment.ts` to measure functional
  accuracy, argument precision, and explicit shell avoidance.
- Token Frugality Metric: Created `metrics/tokenFrugality.ts` to measure and
  penalize conversational noise ("chatter") using a configurable threshold.
- Verification Suite: Added comprehensive unit tests for all metrics, achieving
  100% coverage of scoring logic and gradient steps.
- Project Integration: Relocated `schema.ts` to the core package for build safety,
  updated the data validator, and extended project-wide lint/format scripts.

data/schema.ts

@@ -1,49 +0,0 @@
-/**
- * @license
- * Copyright 2026 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-/**
- * The core data interface for the Tool Alignment Dataset.
- * Designed to be extensible for custom error reports and metrics.
- */
-
-export interface ToolCall {
-  name: string;
-  arguments: Record<string, unknown>;
-}
-
-export interface NegativeExample {
-  id?: string;
-  tool_calls: ToolCall[];
-  output_text?: string; // For "too chatty" or "hallucination" failures
-  reason: string; // e.g., "Defaulted to shell 'cat'", "Included conversational filler"
-  severity: 'low' | 'medium' | 'high'; // Helps the optimizer prioritize fixes
-}
-
-export interface Scenario {
-  id: string; // Unique identifier (e.g., 'read_file-01')
-  metadata: {
-    tags: string[]; // e.g., ['tool-alignment', 'shell-avoidance']
-    created_at: string;
-    platform?: 'darwin' | 'linux' | 'win32'; // To handle platform-specific shell variations
-    model_info?: {
-      // Placeholder for future tracking
-      name?: string;
-      version?: string;
-    };
-  };
-  input: {
-    user_query: string;
-    context?: {
-      current_file?: string;
-      directory_structure?: string[];
-    };
-  };
-  expected: {
-    tool_calls: ToolCall[];
-    rationale: string; // Why this is the 'Golden' choice
-  };
-  negatives: NegativeExample[]; // Array of multiple failure modes
-}