docs: update PRD with Section 9 Phase 3 progress

Updated progress tracker:
- Section 9 now shows Phases 1-3 complete (111 tests, ~50% coverage)
- Added detailed phase breakdown with completion dates
- Updated last modified date to December 14, 2025

Phase summary:
- Phase 1: Test Infrastructure & Model Tests (29 tests)
- Phase 2: Configuration & Field Mapping (44 tests)
- Phase 3: Deduplication Logic Tests (38 tests)

Remaining for Section 9:
- Phase 4: Data Source Tests, Error Handling, CI integration

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: leogdion

.claude/PRD.md

@@ -12,12 +12,12 @@
 - ✅ **Section 6**: XcodeGen Integration - COMPLETED (project.yml configuration)
 - ✅ **Section 7**: Documentation - COMPLETED (DocC catalog, organized markdown docs)
 - ✅ **Section 8**: README Improvements - COMPLETED
-- ⏳ **Section 9**: Unit Testing - In Progress (Phases 1-2 complete: 73 tests, ~40% coverage)
+- ⏳ **Section 9**: Unit Testing - In Progress (Phases 1-3 complete: 111 tests, ~50% coverage)
 - ⏳ **Section 10**: BushelKit Integration - Not started
 - ⏳ **Section 11**: Project Configuration - Not started
 - ⏳ **Section 12**: Release Preparation - Not started
 
-**Last Updated**: December 13, 2025
+**Last Updated**: December 14, 2025
 
 **Note**: CodeRabbit's automated analysis (December 2025) contained several inaccuracies that have been verified and corrected:
 - Progress was reported as 1/12 (8%), but actual progress is 7/12 (58%) as shown above
@@ -177,21 +177,55 @@ BushelCloud is a CloudKit demonstration project showcasing MistKit's CloudKit We
 ## 9. Unit Testing
 **Objective**: Establish comprehensive unit test coverage
 
-**Tasks**:
-- [ ] Create `Tests/BushelCloudTests/` directory
-- [ ] Add test cases for:
-  - **Data Source Tests**: Mock fetchers for IPSW, AppleDB, MESU, Xcode Releases
-  - **CloudKit Record Tests**: Verify `toCloudKitFields()` and `from(recordInfo:)` conversions
-  - **Deduplication Tests**: Verify merge logic in `DataSourcePipeline`
-  - **Reference Resolution Tests**: Verify XcodeVersion references are correctly created
-  - **Error Handling Tests**: Test graceful failures for network errors, auth errors
-- [ ] Add test utilities:
-  - Mock CloudKit service for testing without real CloudKit calls
-  - Sample record fixtures for testing
-  - Helper methods for common test scenarios
+**Status**: Phases 1-3 complete (111 tests, ~50% coverage)
+
+### Phase 1: Test Infrastructure & Model Tests ✅ COMPLETED
+**Completed**: December 13, 2025 | **Tests**: 29
+
+**Deliverables**:
+- [x] Create `Tests/BushelCloudTests/` directory
+- [x] Test utilities (TestFixtures, MockRecordInfo, FieldValueAssertions)
+- [x] Model CloudKit mapping tests:
+  - RestoreImageRecordTests (13 tests)
+  - XcodeVersionRecordTests (7 tests)
+  - SwiftVersionRecordTests (6 tests)
+  - DataSourceMetadataTests (6 tests)
+
+### Phase 2: Configuration & Field Mapping Tests ✅ COMPLETED
+**Completed**: December 13, 2025 | **Tests**: 44 (73 total)
+
+**Deliverables**:
+- [x] FetchConfiguration tests (25 tests)
+  - Minimum interval priority
+  - shouldFetch throttling logic
+  - Default intervals
+  - Codable conformance
+- [x] CloudKitFieldMapping tests (19 tests)
+  - All conversion methods
+  - Optional value handling
+  - Round-trip conversions
+
+### Phase 3: Deduplication Logic Tests ✅ COMPLETED
+**Completed**: December 14, 2025 | **Tests**: 38 (111 total)
+
+**Deliverables**:
+- [x] RestoreImage deduplication & merge tests (21 tests)
+  - MESU authority rules
+  - Timestamp-based merging
+  - Data backfilling
+- [x] XcodeVersion reference resolution tests (9 tests)
+  - Version string matching
+  - REQUIRES field parsing
+- [x] XcodeVersion/SwiftVersion deduplication tests (8 tests)
+
+### Phase 4: Remaining Tests (Not Started)
+**Remaining Tasks**:
+- [ ] Data Source Tests: Mock fetchers for IPSW, AppleDB, MESU, Xcode Releases
+- [ ] Error Handling Tests: Test graceful failures for network errors, auth errors
+- [ ] Mock CloudKit service for testing without real CloudKit calls
 - [ ] Configure test scheme in XcodeGen
 - [ ] Add test coverage reporting to CI
-- [ ] Set minimum coverage threshold (e.g., 70%)
+- [ ] Set minimum coverage threshold (70%)
 
 ## 10. BushelKit Integration
 **Objective**: Add BushelKit dependency and migrate relevant code