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/milestones/M001/slices/S01/S01-PLAN.md

@@ -21,6 +21,7 @@ S01 directly advances active requirements **R001** and **R002**, and it also lay
 
 - `dotnet test JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --filter GmailControllerTests`
 - `CI=true npm --prefix job-tracker-ui test -- --watch=false --runTestsByPath src/correspondence-gmail-import.test.tsx`
+- Failure-path inspection: hit `api/gmail/status` while disconnected and exercise the job-scoped Gmail matching endpoint with an invalid or inaccessible `jobApplicationId`; confirm the API exposes connection state plus a clear `Job application not found.` or validation error response without leaking Gmail content.
 - Manual UAT: run the app, connect a real Gmail account, open one job in the workspace, confirm ranked Gmail suggestions appear before manual search, import one message and one full thread, and verify the imported correspondence appears on that same job with duplicates skipped and no send/apply automation.
 
 ## Observability / Diagnostics
@@ -44,13 +45,13 @@ S01 directly advances active requirements **R001** and **R002**, and it also lay
   - Do: Add a job-scoped Gmail candidate endpoint that loads the owned job plus company context, builds multiple Gmail queries from recruiter/company/title/correspondence signals, dedupes messages and groups them by thread, and returns ranked suggestions with match reasons, confidence inputs, and already-imported flags; cover the contract with focused controller/service tests instead of leaving ranking in `Correspondence.tsx`.
   - Verify: `dotnet test JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --filter GmailControllerTests`
   - Done when: the API can return ranked Gmail candidates for one job with explicit reasons and duplicate state, and backend tests prove owned-job lookup plus ranking/dedupe behavior.
-- [x] **T02: Persist Gmail thread metadata and harden import continuity** `est:3h`
+- [ ] **T02: Persist Gmail thread metadata and harden import continuity** `est:3h`
   - Why: Smarter matching is not enough if imported correspondence still loses thread identity or forces downstream slices to re-derive sender/thread information later.
   - Files: `Models/Correspondence.cs`, `JobTrackerApi/Controllers/GmailController.cs`, `JobTrackerApi/Controllers/CorrespondenceController.cs`, `JobTrackerApi/Program.cs`, `JobTrackerApi.Tests/GmailControllerTests.cs`
   - Do: Extend correspondence persistence and import logic so Gmail imports store thread/message identity plus sender/recipient metadata, update import responses and duplicate handling to reflect imported vs skipped outcomes clearly, and update startup schema guards so older SQLite/MySQL dev databases remain bootable when the new fields land.
   - Verify: `dotnet test JobTrackerApi.Tests/JobTrackerApi.Tests.csproj --filter GmailControllerTests`
   - Done when: imported correspondence keeps enough Gmail metadata for thread continuity and dedupe, compatibility guards are planned with the schema change, and tests prove single-message/thread imports behave correctly on repeat imports.
-- [x] **T03: Wire ranked Gmail suggestions into the job workspace UI** `est:3h`
+- [ ] **T03: Wire ranked Gmail suggestions into the job workspace UI** `est:3h`
   - Why: The slice is only complete when the user can act on the smarter backend contract inside the actual job workspace rather than through a generic inbox search UI.
   - Files: `job-tracker-ui/src/components/JobDetailsDialog.tsx`, `job-tracker-ui/src/components/Correspondence.tsx`, `job-tracker-ui/src/types.ts`, `job-tracker-ui/src/correspondence-gmail-import.test.tsx`
   - Do: Pass job context from `JobDetailsDialog` into `Correspondence`, replace client-side primary ranking with the server-provided candidate contract, show match reasons/confidence/import state and thread actions, keep manual query/search as a fallback override, and add a React test that proves ranked suggestions and import refresh behavior in the dialog.