fix: make FTS5 optional for template search (fixes Claude Desktop compatibility)

- Added runtime FTS5 detection in database adapters
- Removed FTS5 from required schema to prevent "no such module" errors
- FTS5 tables/triggers created conditionally only if supported
- Template search automatically falls back to LIKE when FTS5 unavailable
- Works in ALL SQLite environments (Claude Desktop, restricted envs, etc.)

This ensures search_templates() works correctly regardless of SQLite build,
while still providing optimal performance when FTS5 is available.

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

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

src/templates/template-service.ts

@@ -132,6 +132,11 @@ export class TemplateService {
       }
       
       logger.info(`Successfully saved ${saved} templates to database`);
+      
+      // Rebuild FTS5 index after bulk import
+      logger.info('Rebuilding FTS5 index for templates');
+      this.repository.rebuildTemplateFTS();
+      
       progressCallback?.('Complete', saved, saved);
     } catch (error) {
       logger.error('Error fetching templates:', error);