docs(openspec): add SDD artifact trail for recent alarm and EQ changes

Persist the exploration, proposal, spec, design, tasks, and
verify/archive reports produced during the multi-device EQ,
alarm-countdown, and notification-visual-polish SDD cycles.

openspec/changes/eq-device-autoswitch-ux/state.yaml

@@ -0,0 +1,27 @@
+---
+# SDD Change State
+change_name: eq-device-autoswitch-ux
+artifact_store: hybrid
+status: archived
+archived_date: 2026-06-28
+
+# Artifact references (engram topic_keys)
+artifacts:
+  proposal: sdd/eq-device-autoswitch-ux/proposal
+  spec: sdd/eq-device-autoswitch-ux/spec
+  design: sdd/eq-device-autoswitch-ux/design
+  tasks: sdd/eq-device-autoswitch-ux/tasks
+  apply_progress: sdd/eq-device-autoswitch-ux/apply-progress
+  verify_report: sdd/eq-device-autoswitch-ux/verify-report
+  archive_report: sdd/eq-device-autoswitch-ux/archive-report
+
+# Test verdict
+test_status: all_pass
+test_count: 231
+analyzer_status: clean
+
+# Chained PRs delivered
+pr_count: 3
+pr_1: "feat(eq): add per-device equalizer rename + display name fallback"
+pr_2: "feat(eq): device edit modal + connection indicator"
+pr_3: "test(eq): complete device rename and modal test coverage"