release: cut 1.0.0

Pin compose and local trial to ghcr.io/mixeme/selfpost:1.0.0, close the
CHANGELOG cut, and retire implementation-plan / v1.x-closure-plan.

Includes the post-cut startup fixes needed for a green release e2e gate:
root-owned TLS copies for postfix check, maillog_file_prefixes for /data,
hostname gate and traversable /data, panel /healthz before setup, and
setup-token / TempDir reclaim via docker exec.

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

test/e2e/compose.override.yml

@@ -16,6 +16,10 @@
 
 services:
   selfpost:
+    # Crash-looping with unless-stopped makes `compose exec` fail with
+    # "Container is restarting" and hides the entrypoint/supervisord exit
+    # reason; keep the stand exited so logs stay attached to one attempt.
+    restart: "no"
     build:
       # Resolved relative to --project-directory (.stage), NOT this file's own
       # directory — compose build.context paths follow the project directory,