release: 2.0.0: Panel redesign; new URLs; database from zero

The panel redesign (docs/plans/panel-redesign.md, 27/27). A breaking
release: every panel URL changed and the database starts from a single
baseline - a 1.x /data is not upgraded.

Since the last cut also fixed, all found on the test server:
  - the panel can read the mail queue;
  - port 25 answers with DMARC report ingest on, also next to the
    inbound relay;
  - DMARC reports reach the panel (the delivery service never worked
    since 1.7.0);
  - Postfix start-up warnings about the queue directory.

Cut: CHANGELOG [Unreleased] -> [2.0.0]; image pin 2.0.0 in compose,
README, guide; roadmap, plan and version table.

On the test server, on 252e5d1: go vet ./... ok, go test ./... ok
(22 packages), make e2e ok.

Full detail: CHANGELOG.md (2.0.0).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/plans/panel-redesign.md

@@ -1,6 +1,6 @@
 # Plan: panel-redesign
 
-**Status:** agreed (owner, 2026-10-09)  
+**Status:** shipped in `2.0.0` (2026-10-11)  
 **Date:** 2026-09-21 (replaces the 2026-09-08 givens)  
 **Version:** `2.0.0` MAJOR — a breaking release by the owner's decision (§ No compatibility).
 
@@ -532,7 +532,7 @@ only when both are done. Every stage-2 step ends with the evidence of
 - [x] Technical review of the whole against the mockups, evidence pairs complete — **Opus**
 - [x] Security review of the route rename, subtree authorization and inbound delegation — **Fable**
 - [x] guide.md screenshots and wording for the new navigation; architecture.md § Panel HTTP surface and § Persistence; security.md roles; *Removed* in the CHANGELOG with one line that 2.0 starts from an empty data directory; strike the three UI rows of review-2026-08-followups that the redesign retires — **Sonnet**
-- [ ] `go vet`, `go test ./...`, e2e suite; version cut `2.0.0` — **Haiku**
+- [x] `go vet`, `go test ./...`, e2e suite; version cut `2.0.0` — **Haiku**
 
 **After 2.0** — features land in the kit, each from its own plan, mockup first
 (§ Room for roadmap items): inbound-antispam-panel `2.1.0`; then, in whatever