feat(export): Replace CSV export with standardized JSON format

- Add contactsToExportJson utility function for standardized data export
- Replace CSV export with JSON format in DataExportSection
- Update file extension and MIME type to application/json
- Remove Dexie-specific export logic in favor of unified SQLite/Dexie approach
- Update success notifications to reflect JSON format
- Add TypeScript interfaces for export data structure

This change improves data portability and standardization by:
- Using a consistent JSON format for data export/import
- Supporting both SQLite and Dexie databases
- Including all contact fields in export
- Properly handling contactMethods as stringified JSON
- Maintaining backward compatibility with existing import tools

Security: No sensitive data exposure, maintains existing access controls

src/views/ProjectViewView.vue

@@ -389,7 +389,12 @@
                     {{ libsUtil.formattedAmount(givenTotalHours(), "HUR") }}
                   </span>
                   <span v-else>
-                    {{ libsUtil.formattedAmount(givesTotalsByUnit[0].amount, givesTotalsByUnit[0].unit) }}
+                    {{
+                      libsUtil.formattedAmount(
+                        givesTotalsByUnit[0].amount,
+                        givesTotalsByUnit[0].unit,
+                      )
+                    }}
                   </span>
                   <span v-if="givesTotalsByUnit.length > 1">...</span>
                   <span>