feat: add incremental template updates and fix metadata generation

Template Updates:
- Add npm script for incremental template fetch (fetch:templates:update)
- Create MEMORY_TEMPLATE_UPDATE.md with comprehensive documentation
- Update 48 new templates (2598 → 2646 total)
- Latest template now from September 24, 2025

Metadata Generation Fixes:
- Update model from gpt-4o-mini to gpt-5-mini-2025-08-07
- Remove temperature parameter (not supported in batch API)
- Increase max_completion_tokens from 1000 to 3000
- Add comprehensive error file handling to batch-processor
- Process failed requests and assign default metadata
- Save error files for debugging (temp/batch/)

Test Updates:
- Update all test files to use gpt-5-mini-2025-08-07 model
- 3 test assertions updated in metadata-generator.test.ts
- 1 test option updated in batch-processor.test.ts

Documentation:
- Add troubleshooting section for metadata generation
- Include error handling examples
- Document incremental vs full rebuild modes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/unit/templates/batch-processor.test.ts

@@ -71,7 +71,7 @@ describe('BatchProcessor', () => {
     
     options = {
       apiKey: 'test-api-key',
-      model: 'gpt-4o-mini',
+      model: 'gpt-5-mini-2025-08-07',
       batchSize: 3,
       outputDir: './test-temp'
     };