docs(08): create phase 8 cron reporting plans

- 08-01-PLAN.md: Archive script (DRY_RUN toggle) + daily report cron (skill-backed)
- 08-02-PLAN.md: Weekly stale summary cron + weekly archive cron (no_agent)
- ROADMAP.md: Updated Phase 8 plans count to 2

Covers CRON-01 (daily report), CRON-02 (stale archive script+cron),
CRON-03 (Jira integration in daily/weekly reports).

.planning/ROADMAP.md

@@ -83,7 +83,11 @@ Plans:
   3. Daily report includes Jira ticket status for active sessions via ngn-jira skill
   4. Sessions inactive >30d are archived to JSON with no data loss (export-before-delete verified)
   5. Archive script supports dry-run mode for safe initial testing before activating cron
-**Plans**: TBD
+**Plans**: 2 plans
+
+Plans:
+- [ ] 08-01-PLAN.md — Archive script + daily report cron (Wave 1)
+- [ ] 08-02-PLAN.md — Weekly stale summary + archive cron (Wave 2)
 
 ### Phase 9: Tooling & Portable Setup
 **Goal**: Custom Docker image with essential platform engineering tools (AWS CLI, Terraform, Helm, kubectl, Datadog CLI) and a portable setup script that can configure a fresh machine with all ngn-agent config in one invocation
@@ -108,5 +112,5 @@ Plans:
 | 5. Hindsight Memory Provider | v1.1 | 1/1 | Complete | 2026-06-14 |
 | 6. Default Repos & SSH Mount | v1.1 | 1/1 | Complete | 2026-06-14 |
 | 7. Main Session Skill | v1.1 | 1/1 | Complete | 2026-06-14 |
-| 8. Cron Reporting | v1.1 | 0/TBD | Not started | - |
+| 8. Cron Reporting | v1.1 | 0/2 | Not started | - |
 | 9. Tooling & Portable Setup | v1.1 | 0/TBD | Not started | - |