docs: update decisions index and task index for garden module and adr backfill

Populates the decisions index with the two existing ADRs (list SSE/notify,
release workflow). Adds task 09 to the phase 1 list and adds the phase 8
garden module task entries to the task index.

docs/tasks/README.md

@@ -33,6 +33,7 @@ Every task file has these sections:
 - [06 — Authentik install + OIDC integration](06-authentik-oidc.md)
 - [07 — Household seeding & session](07-household-seed.md)
 - [08 — Theming infrastructure (multi-theme + dark mode)](08-theming.md)
+- [09 — Pre-deploy checklist (recurring)](09-pre-deploy-checklist.md)
 
 ### Phase 2 — Core modules
 
@@ -69,3 +70,12 @@ Every task file has these sections:
 - [60 — Postgres backups (pg_dump cron)](60-backups.md)
 - [61 — Rate limiting on share links](61-rate-limit.md)
 - [62 — Structured logging](62-logging.md)
+
+### Phase 8 — Garden module
+
+- [70 — Garden infrastructure (MinIO + upload route + schema)](70-garden-infrastructure.md)
+- [71 — Garden containers](71-garden-containers.md)
+- [72 — Garden plants](72-garden-plants.md)
+- [73 — Garden care tracking](73-garden-care-tracking.md)
+- [74 — Garden integrations](74-garden-integrations.md)
+- [75 — Garden dashboard](75-garden-dashboard.md)