test(S01/T01): Added a job-scoped Gmail matching contract with backend-…

- JobTrackerApi/Controllers/GmailController.cs
- JobTrackerApi/Services/GmailOAuthService.cs
- JobTrackerApi.Tests/GmailControllerTests.cs
- .gsd/milestones/M001/slices/S01/S01-PLAN.md
- .gsd/KNOWLEDGE.md

.gsd/OVERRIDES.md

@@ -0,0 +1,12 @@
+# GSD Overrides
+
+User-issued overrides that supersede plan document content.
+
+---
+## Override: 2026-03-24T10:57:41.499Z
+
+**Change:** can the gmail import bring the while tread of emails though? and also update automatically so if i reply to an email itll ahow my responce automaticslly without havjng to repull/kmport the emaila
+**Scope:** active
+**Applied-at:** M001/S01/T01
+
+---