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/metadata-generator.test.ts

@@ -18,7 +18,7 @@ describe('MetadataGenerator', () => {
   let generator: MetadataGenerator;
   
   beforeEach(() => {
-    generator = new MetadataGenerator('test-api-key', 'gpt-4o-mini');
+    generator = new MetadataGenerator('test-api-key', 'gpt-5-mini-2025-08-07');
   });
   
   describe('createBatchRequest', () => {
@@ -35,7 +35,7 @@ describe('MetadataGenerator', () => {
       expect(request.custom_id).toBe('template-123');
       expect(request.method).toBe('POST');
       expect(request.url).toBe('/v1/chat/completions');
-      expect(request.body.model).toBe('gpt-4o-mini');
+      expect(request.body.model).toBe('gpt-5-mini-2025-08-07');
       expect(request.body.response_format.type).toBe('json_schema');
       expect(request.body.response_format.json_schema.strict).toBe(true);
       expect(request.body.messages).toHaveLength(2);
@@ -217,7 +217,7 @@ describe('MetadataGenerator', () => {
       // but should not cause any injection in our code
       expect(userMessage).toContain('<script>alert("xss")</script>');
       expect(userMessage).toContain('javascript:alert(1)');
-      expect(request.body.model).toBe('gpt-4o-mini');
+      expect(request.body.model).toBe('gpt-5-mini-2025-08-07');
     });
 
     it('should handle extremely long template names', () => {