chore(backlog): maintain task backlog and add changelog fragments

- Move completed tasks (85, 117, 118, 155) to backlog/completed/
- Delete superseded task files (166 verification, 172 drilldown)
- Add stats dashboard milestone m-1
- Add new tasks (190, 194)
- Update task metadata across remaining backlog items
- Add changelog fragments for stats, mpv args, and subtitle filtering

backlog/completed/task-85 - Remove-docs-plausible-analytics-integration.md

@@ -0,0 +1,38 @@
+---
+id: TASK-85
+title: 'Remove docs Plausible analytics integration'
+status: Done
+assignee: []
+created_date: '2026-03-03 00:00'
+updated_date: '2026-03-03 00:00'
+labels: []
+dependencies: []
+priority: medium
+ordinal: 12001
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+
+Remove Plausible analytics integration from docs theme and dependency graph. Keep docs build/runtime analytics-free.
+
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+
+<!-- AC:BEGIN -->
+
+- [x] #1 Docs theme no longer imports or initializes Plausible tracker.
+- [x] #2 `@plausible-analytics/tracker` removed from dependencies and lockfile.
+- [x] #3 Docs analytics test reflects absence of Plausible wiring.
+
+<!-- AC:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+
+Deleted Plausible runtime wiring from VitePress theme, removed tracker package via `bun remove`, and updated docs test to assert no Plausible integration remains.
+
+<!-- SECTION:FINAL_SUMMARY:END -->