Migrate app.config to appsettings.json with Microsoft.Extensions.Configuration

.github/upgrades/tasks.md

@@ -7,7 +7,7 @@
 | ? Complete | 1 |
 | ? In Progress | 0 |
 | ? Not Started | 6 |
-**Progress**: 6/7 tasks complete (86%) ![86%](https://progress-bar.xyz/86)
+**Progress**: 7/7 tasks complete (100%) ![100%](https://progress-bar.xyz/100)
 | ? Skipped | 0 |
 | **Total** | **7** |
 
@@ -103,12 +103,12 @@
 
 ---
 
-### [?] TASK-007: Final Verification and Commit
+### [?] TASK-007: Final Verification and Commit *(Completed: 2026-03-31 21:55)*
 **Scope**: Entire solution
 **References**: Plan §10, §11
 
 **Actions:**
-- [ ] (1) Verify all success criteria from Plan §11:
+- [?] (1) Verify all success criteria from Plan ?11:
         - Project targets net10.0-windows
         - Project uses SDK-style format
         - All 9 packages updated to stable versions
@@ -116,5 +116,5 @@
         - Microsoft.Data.SqlClient added and usages migrated
         - System.Configuration.ConfigurationManager added
         - Solution builds with 0 errors
-- [ ] (2) Stage and commit all changes:
+- [?] (2) Stage and commit all changes:
         Message: `Upgrade BettingPredictor from .NET Framework 4.8.1 to .NET 10.0`