ML-169: add subtasks

backlog/tasks/ml-169.3 - Phase-2-PubSub-subscription-lifecycle-audit.md

@@ -0,0 +1,39 @@
+---
+id: ML-169.3
+title: "Phase 2: PubSub subscription lifecycle audit"
+status: To Do
+assignee: []
+created_date: "2026-05-08 08:59"
+labels:
+  - audit
+  - pubsub
+dependencies: []
+references:
+  - lib/music_library/records.ex
+  - lib/music_library/listening_stats.ex
+  - lib/music_library_web/live_helpers/record_actions.ex
+parent_task_id: ML-169
+priority: medium
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+
+Audit all PubSub subscribe/unsubscribe pairs for correctness. Verify no stale subscriptions or double-subscription risks.
+
+Pre-flagged concern: ListeningStats.subscribe() is called in mount by StatsLive.Index and ScrobbledTracksLive.Index but never unsubscribed. Phoenix.PubSub monitors PID for auto-cleanup, but double-subscription on LiveView reconnect is possible and needs verification.
+
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+
+<!-- AC:BEGIN -->
+
+- [ ] #1 Records.subscribe/1 and Records.unsubscribe/1 call sites audited — confirmed only called via manage_subscription/2 in Show LiveViews
+- [ ] #2 manage_subscription/2 verified correct across all navigation paths (direct URL, browser back/forward, push_navigate, push_patch)
+- [ ] #3 ListeningStats.subscribe() double-subscription risk on reconnect evaluated — either confirmed safe by PID monitoring or flagged with fix
+- [ ] #4 Termination cleanup verified: Phoenix.PubSub auto-cleans on PID death confirmed; any manual unsubscribe gaps documented
+- [ ] #5 Records.notify_update/1 broadcast sites audited against intended behavior (coordinates with Phase 3 worker audit)
+- [ ] #6 Findings report written as a Backlog.md document with file:line references, severity ratings, and fix recommendations
+<!-- AC:END -->