Complete task 4 backend security architecture docs

Taskmaster/Tasks/task-4-8.md

@@ -1,23 +1,23 @@
 ---
 taskmaster_id: "4.8"
-status: "pending"
+status: "done"
 priority: "medium"
 depends_on: ["2", "3", "4", "5", "6", "7"]
 parent_id: "4"
 source: "taskmaster"
-generated_at: "2026-05-24T07:15:25.199Z"
+generated_at: "2026-05-24T07:26:29.052Z"
 ---
 
 # 4.8 - Make backend-core stack decision
 
-- [ ] 4.8 - Make backend-core stack decision #taskmaster #priority/medium #status/pending 🔼 🆔 tm-4-8 ⛔ tm-2 ⛔ tm-3 ⛔ tm-4 ⛔ tm-5 ⛔ tm-6 ⛔ tm-7
+- [x] 4.8 - Make backend-core stack decision #taskmaster #priority/medium #status/done 🔼 🆔 tm-4-8 ⛔ tm-2 ⛔ tm-3 ⛔ tm-4 ⛔ tm-5 ⛔ tm-6 ⛔ tm-7
 
 ## Metadata
 
 | Field | Value |
 | --- | --- |
 | Taskmaster ID | 4.8 |
-| Status | pending |
+| Status | done |
 | Priority | medium |
 | Dependencies | 2, 3, 4, 5, 6, 7 |
 | Parent | 4 - Define backend security and refactor strategy from latest audit |
@@ -28,6 +28,8 @@ Choose whether the security-critical backend core remains TypeScript or moves to
 
 ## Details
 
+Completed. Produced `09 - Audits/Backend Core Stack Decision Record - 2026-05-24.md`.
+
 Evaluate team capability, two-year maintainability, operational footprint, rewrite cost, dual-stack complexity, auditability, supply-chain exposure, and which modules belong in a payment/auth/escrow core versus the existing marketplace/chat API.
 
 ## Verification