release: cut 1.0.0

Pin compose and local trial to ghcr.io/mixeme/selfpost:1.0.0, close the
CHANGELOG cut, retire implementation-plan and v1.x-closure-plan, and point
e2e/CI comments at development.md.

Co-Authored-By: Composer <noreply@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

CHANGELOG.md

@@ -5,6 +5,8 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
 
 ## [Unreleased]
 
+## [1.0.0] - 2026-08-09
+
 ### Added
 
 - A **Delivery log** on each delivery's page (`/deliveries/{id}`): the
@@ -61,10 +63,10 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   layering and route table match `web`→`store` and `POST /domains/import`;
   OpenDKIM drops to `opendkim` via `UserID`; guide drops the archived
   "spec 7.5" pointer, clarifies `POSTFIX_SENDER_LOGIN_MAPS` vs panel writes,
-  and states logrotate keeps 14 daily files. Intermediate CHANGELOG cuts vs
-  the still-pinned compose `0.1.0` image are called out in the guide and
-  `development.md`. Roadmap / implementation-plan point at CHANGELOG
-  `[0.5.0]` Security and refreshed `internal/web` size / symbol links.
+  and states logrotate keeps 14 daily files. Intermediate CHANGELOG cuts from
+  before the published `1.0.0` image are called out in the guide and
+  `development.md`. Roadmap points at CHANGELOG `[0.5.0]` Security and
+  refreshed `internal/web` size / symbol links.
 - Full backups no longer carry `/data/log`. It is Postfix's raw log plus its
   fourteen rotated copies — diagnostic output rather than state to restore, and
   otherwise by far the largest thing in the archive.
@@ -94,6 +96,11 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   dev-host-specific workflow and `mixfed.ru` references removed from docs.
 - `docs/development.md` and `.cursor/rules/agent-rules.mdc` translated to
   English; `roadmap.md` remains Russian (internal tracker).
+- Deploy pin and local-trial image tag set to `ghcr.io/mixeme/selfpost:1.0.0`
+  (compose and git tag `v1.0.0` cut together). Retired
+  `docs/implementation-plan.md` and `docs/v1.x-closure-plan.md`; Makefile,
+  `release.yml`, and e2e comments point at `docs/development.md`. Roadmap
+  v1.x documentation/deploy tail closed.
 
 ## [0.6.0] - 2026-08-08