[Stephen Griffin (stephenegriffin)]

Summary

Fixes #612.

• Serialize accepted multivalue rows even when their contents have not changed. An untouched empty string row must return a typed, terminated value instead of leaving the output uninitialized for the caller.
• Preserve the existing early return for unchanged ordinary (non-MV-row) properties.
• Merge the latest main into the fix branch before submission. The diff against main remains limited to the serialization guard and its comment.

Validation

• Existing Debug x64 and x86 build tasks pass with no warnings or errors.
• Complete existing native suites pass: 261/261 on x64 and 261/261 on x86 after merging main.
• Earlier focused policy checks covered the four dirty/unchanged and MV/ordinary combinations. These were local decision checks, not persistent native editor regression tests.
• The existing unit-test project does not exercise the property-editor UI. Follow-up Expand native test coverage to property editors and multivalue row editing #1022 tracks expanding the framework to test the actual editor serialization and MV-row handling without interactive dialogs or an installed MAPI provider.

[github-actions]

Test Results

    8 files  ±0      8 suites  ±0   41s ⏱️ -9s
  261 tests ±0    261 ✅ ±0  0 💤 ±0  0 ❌ ±0 
2 088 runs  ±0  2 088 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit de4883d. ± Comparison against base commit 37f89e8.