fix(plan): correct test selector to TestFunc_ParseTimestamp

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: michaelmcnees

docs/superpowers/plans/2026-03-24-data-transformation.md

@@ -1147,7 +1147,7 @@ func customFunctions() []cel.EnvOption {
 
 - [ ] **Step 4: Run tests to verify they pass**
 
-Run: `go test ./internal/cel/ -run "TestFunc_Timestamp|TestFunc_FormatTimestamp" -v`
+Run: `go test ./internal/cel/ -run "TestFunc_ParseTimestamp|TestFunc_FormatTimestamp" -v`
 Expected: PASS
 
 - [ ] **Step 5: Run full test suite**