Child issues created with --parent were missing from export_hashes table,
which affects integrity tracking and future incremental export features.
This fix ensures SetExportHash() is called for all exported issues:
- Updated ExportResult to include IssueContentHashes map
- Updated finalizeExport() to call SetExportHash() for each exported issue
- Updated exportToJSONLDeferred() to collect content hashes during export
- Updated performIncrementalExport() to collect content hashes for dirty issues
- Updated exportToJSONLWithStore() to call SetExportHash() after export
- Updated daemon's handleExport() to call SetExportHash() after export
Added test TestExportPopulatesExportHashes to verify the fix works for
both regular and hierarchical (child) issue IDs.
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
810192157c