chore: add changeset for generateObject migration

.changeset/gentle-cats-dance.md

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+---
+"task-master-ai": minor
+---
+
+Migrate AI services to use generateObject for structured data generation
+
+This update migrates all AI service calls from generateText to generateObject, ensuring more reliable and structured responses across all commands.
+
+### Key Changes:
+
+- **Unified AI Service**: Replaced separate generateText implementations with a single generateObjectService that handles structured data generation
+- **JSON Mode Support**: Added proper JSON mode configuration for providers that support it (OpenAI, Anthropic, Google, Groq)
+- **Schema Validation**: Integrated Zod schemas for all AI-generated content with automatic validation
+- **Provider Compatibility**: Maintained compatibility with all existing providers while leveraging their native structured output capabilities
+- **Improved Reliability**: Structured output generation reduces parsing errors and ensures consistent data formats
+
+### Technical Improvements:
+
+- Centralized provider configuration in `ai-providers-unified.js`
+- Added `generateObject` support detection for each provider
+- Implemented proper error handling for schema validation failures
+- Maintained backward compatibility with existing prompt structures
+
+### Bug Fixes:
+
+- Fixed subtask ID numbering issue where AI was generating inconsistent IDs (101-105, 601-603) instead of sequential numbering (1, 2, 3...)
+- Enhanced prompt instructions to enforce proper ID generation patterns
+- Ensured subtasks display correctly as X.1, X.2, X.3 format
+
+This migration improves the reliability and consistency of AI-generated content throughout the Task Master application.