docs(08.1, 09): insert agent output schema phase, update phase 9

Phase 8.1: Agent Output Schema (INSERTED)
- 2 plans in 2 waves (sequential)
- Defines discriminated union schema (done/question/error)
- Updates ClaudeAgentManager to use --json-schema flag
- Aligns MockAgentManager with new schema

Phase 9: Extended Scenarios (updated)
- 2 plans in 1 wave (parallel)
- Now depends on Phase 8.1
- Updated scenario format references

.planning/ROADMAP.md

@@ -141,20 +141,32 @@ Plans:
 - [x] 08-01: Happy Path E2E Tests
 - [x] 08-02: Edge Case E2E Tests
 
-#### Phase 9: Extended Scenarios & CI
+#### Phase 8.1: Agent Output Schema (INSERTED)
 
-**Goal**: Additional scenario coverage + CI pipeline integration for automated test runs
+**Goal**: Define structured agent output schema (done/question/error discriminated union) and update ClaudeAgentManager to use `--json-schema` flag for validated output parsing
 **Depends on**: Phase 8
-**Research**: Unlikely (standard CI patterns)
-**Plans**: TBD
+**Research**: Unlikely (Zod schemas, Claude CLI flags documented)
+**Plans**: 2 plans
 
 Plans:
-- [ ] 09-01: TBD (run /gsd:plan-phase 9 to break down)
+- [ ] 08.1-01: Agent Output Schema & ClaudeAgentManager
+- [ ] 08.1-02: MockAgentManager Schema Alignment
+
+#### Phase 9: Extended Scenarios
+
+**Goal**: Extended E2E scenario coverage — conflict hand-back round-trip, multi-agent parallel work, recovery/resume flows
+**Depends on**: Phase 8.1
+**Research**: Unlikely (testing existing functionality)
+**Plans**: 2 plans
+
+Plans:
+- [ ] 09-01: Conflict & Parallel E2E Tests
+- [ ] 09-02: Recovery & Resume E2E Tests
 
 ## Progress
 
 **Execution Order:**
-Phases execute in numeric order: 1 → 1.1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9
+Phases execute in numeric order: 1 → 1.1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 8.1 → 9
 
 | Phase | Milestone | Plans Complete | Status | Completed |
 |-------|-----------|----------------|--------|-----------|
@@ -167,7 +179,8 @@ Phases execute in numeric order: 1 → 1.1 → 2 → 3 → 4 → 5 → 6 → 7
 | 6. Coordination | v1.0 | 3/3 | Complete | 2026-01-30 |
 | 7. Mock Agent & Test Harness | v1.1 | 2/2 | Complete | 2026-01-31 |
 | 8. E2E Scenario Tests | v1.1 | 2/2 | Complete | 2026-01-31 |
-| 9. Extended Scenarios & CI | v1.1 | 0/? | Not started | - |
+| 8.1. Agent Output Schema | v1.1 | 0/2 | Not started | - |
+| 9. Extended Scenarios | v1.1 | 0/2 | Not started | - |
 
 ---
 *Roadmap created: 2026-01-30*