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

.gitignore

@@ -61,3 +61,26 @@ target/
 vendor/
 .cache/
 tmp/
+
+# ── GSD: Runtime / Ephemeral (per-developer, per-session) ──────────────────
+# Crash detection sentinel — PID lock, written per auto-mode session
+.gsd/auto.lock
+# Auto-mode dispatch tracker — prevents re-running completed units
+.gsd/completed-units.json
+# Derived state cache — regenerated from plan/roadmap files on disk
+.gsd/STATE.md
+# Per-developer token/cost accumulator
+.gsd/metrics.json
+# Raw JSONL session dumps — crash recovery forensics, auto-pruned
+.gsd/activity/
+# Unit execution records — dispatch phase, timeouts, recovery tracking
+.gsd/runtime/
+# Git worktree working copies
+.gsd/worktrees/
+# Parallel orchestration IPC and worker status
+.gsd/parallel/
+# Generated HTML reports (regenerable via /gsd export --html)
+.gsd/reports/
+# Session-specific interrupted-work markers
+.gsd/milestones/**/continue.md
+.gsd/milestones/**/*-CONTINUE.md