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/archive/2026-06-30-pre-notice-live-countdown/state.yaml

@@ -0,0 +1,22 @@
+change_name: pre-notice-live-countdown
+status: archived
+archived_date: 2026-06-30
+verdict: PASS WITH WARNINGS
+critical_issues: 0
+
+artifacts:
+  proposal: proposal.md
+  spec: specs/alarm-pre-notice-countdown/spec.md
+  design: design.md
+  tasks: tasks.md
+  apply_progress: (completed in previous phase)
+  verify_report: verify-report.md
+  archive_report: archive-report.md
+
+completion_notes: |
+  All 4 in-scope implementation/code-inspection sections (1-4) are complete and correct.
+  Critical correctness gate (slot 9 via AlarmScheduler.requestCode formula for both arm and cancel)
+  is verifiably satisfied. Flutter analyze clean. Diff scope: 91 lines (Kotlin-only).
+
+  Manual device QA (section 5) is a follow-up item, not blocking archive.
+  Documented warning: Manual/device QA should be run before/shortly after merge.