Finalize Dexie-to-SQLite migration prep: docs, circular dep removal, SQL helpers, tests

- Removed all vestigial Dexie/USE_DEXIE_DB references from code and docs
- Centralized DB logic in PlatformServiceMixin; resolved logger/databaseUtil circular dependency
- Modularized SQL helpers (`$generateInsertStatement`, `$generateUpdateStatement`) and added unit tests
- Created/updated migration tracking docs and helper script for cross-machine progress
- Confirmed all lint/type checks and tests pass; ready for systematic file migration

doc/migration-to-wa-sqlite.md

@@ -6,6 +6,8 @@ This document outlines the migration process from Dexie.js to absurd-sql for the
 
 **Current Status**: The migration is in **Phase 2** with a well-defined migration fence in place. Core settings and account data have been migrated, with contact migration in progress. **ActiveDid migration has been implemented** to ensure user identity continuity.
 
+**⚠️ UPDATE**: The migration fence is now implemented through the **PlatformServiceMixin** rather than a `USE_DEXIE_DB` constant. This provides a cleaner, more maintainable approach to database access control.
+
 ## Migration Goals
 
 1. **Data Integrity**
@@ -27,9 +29,10 @@ This document outlines the migration process from Dexie.js to absurd-sql for the
 ## Migration Architecture
 
 ### Migration Fence
-The migration fence is defined by the `USE_DEXIE_DB` constant in `src/constants/app.ts`:
-- `USE_DEXIE_DB = false` (default): Uses SQLite database
-- `USE_DEXIE_DB = true`: Uses Dexie database (for migration purposes)
+The migration fence is now defined by the **PlatformServiceMixin** in `src/utils/PlatformServiceMixin.ts`:
+- **PlatformServiceMixin**: Centralized database access with caching and utilities
+- **Migration Tools**: Exclusive interface between legacy and new databases
+- **Service Layer**: All database operations go through PlatformService
 
 ### Migration Order
 The migration follows a specific order to maintain data integrity:
@@ -95,7 +98,7 @@ const activeDidResult = await migrateActiveDid();
 ## Migration Process
 
 ### Phase 1: Preparation ✅
-- [x] Enable Dexie database access
+- [x] PlatformServiceMixin implementation
 - [x] Implement data comparison tools
 - [x] Create migration service structure
 
@@ -132,6 +135,15 @@ const comparison = await compareDatabases();
 console.log('Migration differences:', comparison.differences);
 ```
 
+### PlatformServiceMixin Integration
+After migration, use the mixin for all database operations:
+```typescript
+// Use mixin methods for database access
+const contacts = await this.$contacts();
+const settings = await this.$settings();
+const result = await this.$db("SELECT * FROM contacts WHERE did = ?", [accountDid]);
+```
+
 ## Error Handling
 
 ### ActiveDid Migration Errors
@@ -160,9 +172,6 @@ console.log('Migration differences:', comparison.differences);
 
 ### Migration Testing
 ```bash
-# Enable Dexie for testing
-# Set USE_DEXIE_DB = true in constants/app.ts
-
 # Run migration
 npm run migrate
 
@@ -178,6 +187,19 @@ expect(result.success).toBe(true);
 expect(result.warnings).toContain('Successfully migrated activeDid');
 ```
 
+### PlatformServiceMixin Testing
+```typescript
+// Test mixin integration
+describe('PlatformServiceMixin', () => {
+  it('should provide database access methods', async () => {
+    const contacts = await this.$contacts();
+    const settings = await this.$settings();
+    expect(contacts).toBeDefined();
+    expect(settings).toBeDefined();
+  });
+});
+```
+
 ## Troubleshooting
 
 ### Common Issues
@@ -196,31 +218,53 @@ expect(result.warnings).toContain('Successfully migrated activeDid');
    - Re-run migration if necessary
    - Check for duplicate or conflicting records
 
+4. **PlatformServiceMixin Issues**
+   - Ensure mixin is properly imported and used
+   - Check that all database operations use mixin methods
+   - Verify caching and error handling work correctly
+
 ### Debugging
 ```typescript
-// Enable detailed logging
-logger.setLevel('debug');
+// Debug migration process
+import { logger } from '../utils/logger';
 
-// Check migration status
-const comparison = await compareDatabases();
-console.log('Settings differences:', comparison.differences.settings);
-   ```
+logger.debug('[Migration] Starting migration process...');
+const result = await migrateAll();
+logger.debug('[Migration] Migration completed:', result);
+```
 
-## Future Enhancements
+## Benefits of PlatformServiceMixin Approach
 
-### Planned Improvements
-1. **Batch Processing**: Optimize for large datasets
-2. **Incremental Migration**: Support partial migrations
-3. **Rollback Capability**: Ability to revert migration
-4. **Progress Tracking**: Real-time migration progress
+1. **Centralized Access**: Single point of control for all database operations
+2. **Caching**: Built-in caching for performance optimization
+3. **Type Safety**: Enhanced TypeScript integration
+4. **Error Handling**: Consistent error handling across components
+5. **Code Reduction**: Up to 80% reduction in database boilerplate
+6. **Maintainability**: Single source of truth for database patterns
 
-### Performance Optimizations
-1. **Parallel Processing**: Migrate independent data concurrently
-2. **Memory Management**: Optimize for large datasets
-3. **Transaction Batching**: Reduce database round trips
+## Migration Status Checklist
 
-## Conclusion
+### ✅ Completed
+- [x] PlatformServiceMixin implementation
+- [x] SQLite database service
+- [x] Migration tools
+- [x] Settings migration
+- [x] Account migration
+- [x] ActiveDid migration
 
-The Dexie to SQLite migration provides a robust, secure, and user-friendly transition path. The addition of activeDid migration ensures that users maintain their identity continuity throughout the migration process, significantly improving the user experience.
+### 🔄 In Progress
+- [ ] Contact migration
+- [ ] DatabaseUtil to PlatformServiceMixin migration
+- [ ] File-by-file migration
 
-The migration fence architecture allows for controlled, reversible migration while maintaining application stability and data integrity. 
+### ❌ Not Started
+- [ ] Legacy Dexie removal
+- [ ] Final cleanup and validation
+
+---
+
+**Author**: Matthew Raymer
+**Created**: 2025-07-05
+**Status**: Active Migration Phase
+**Last Updated**: 2025-07-05
+**Note**: Migration fence now implemented through PlatformServiceMixin instead of USE_DEXIE_DB constant