docs: consolidate OTA 1.8.0 + master-plan open items into one priority-ordered tracker

docs/UNIFIED-TASK-TRACKER.md replaces hunting across SESSION-1.8.0-OTA-PROGRESS.md
and PRODUCTION-MASTER-PLAN.md for "what's left" — fastest/simplest tasks first.
Verified against live code/nodes rather than trusting doc text: several previously
"open" items (bind-dir chown, netbird legacy installer, launch-port fallback,
archival-bitcoin manifest field, progress-UI monotonicity, all-apps coverage,
fedimint test coverage, changelog backfill, portainer image pin, grafana quadlet
activation) turned out already shipped or non-issues, and are closed out here.
TESTING.md's release-gate checklist updated to match reality (cargo warnings,
5x gate, changelog already green; multinode/backend-default-flip/tag genuinely open).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CLAUDE.md

@@ -6,6 +6,11 @@
 criterion is met and the priority banner is demoted. Next exit-criteria: the
 **multinode pass** (`docs/multinode-testing-plan.md`) and workstreams B/C/D.
 
+**For day-to-day work, use `docs/UNIFIED-TASK-TRACKER.md`** — the consolidated,
+priority-ordered "what's left" list across the 1.8.0 OTA and master-plan docs
+(fastest/simplest tasks first). It supersedes hunting through the two source docs
+below for open items; those remain the narrative/history.
+
 **Read `docs/PRODUCTION-MASTER-PLAN.md` first** — it is still the authoritative plan
 for the north star: a world-class, **developer-ready app platform** where every app
 is manifest-driven, manifests ship via the **signed registry** (not OTA disk files),