docs: mark Phase 3 complete in REFACTORING_PLAN.md

Author: brandonkachen

REFACTORING_PLAN.md

@@ -51,10 +51,10 @@ This document outlines a prioritized refactoring plan for the 51 issues identifi
 ### Phase 3 Progress
 | Commit | Description | Status | Completed By |
 |--------|-------------|--------|-------------|
-| 3.1 | DRY up auto-topup logic | ⬜ Not Started | - |
-| 3.2 | Split db/schema.ts | ⬜ Not Started | - |
-| 3.3 | Remove dead code batch 1 | ⬜ Not Started | - |
-| 3.4 | Remove dead code batch 2 | ⬜ Not Started | - |
+| 3.1 | DRY up auto-topup logic | ✅ Complete | Codebuff |
+| 3.2 | Split db/schema.ts | ✅ Complete | Codebuff |
+| 3.3 | Remove dead code batch 1 | ✅ Complete | Codebuff |
+| 3.4 | Remove dead code batch 2 | ✅ Complete | Codebuff |
 
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