chore(release): drop Windows target, extend stop grace, document single-replica

The Windows release shipped a zip that self-update cannot extract, so
remove the Windows platform, matrix leg, and its dead archive handling
rather than add zip support. Raise the compose stop grace period above the
serial drain plus worker-shutdown budget so Docker does not SIGKILL mid
shutdown. Record that the deployment is single-replica and why, since the
worker leader lease and self-update swap are per-replica.

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/release.yml

@@ -105,7 +105,7 @@ jobs:
               require_string(platform, key, "#{platforms_path}: platforms[#{index}]")
             end
             archive = platform["archive"]
-            fail("#{platforms_path}: platforms[#{index}].archive must be tar.gz or zip") unless ["tar.gz", "zip"].include?(archive)
+            fail("#{platforms_path}: platforms[#{index}].archive must be tar.gz") unless archive == "tar.gz"
             platform_key = "#{platform["os"]}-#{platform["arch"]}"
             fail("#{platforms_path}: duplicate platform #{platform_key}") if seen_platforms[platform_key]
             seen_platforms[platform_key] = true
@@ -324,7 +324,6 @@ jobs:
           import pathlib
           import shutil
           import tarfile
-          import zipfile
 
           APP_NAME = "codex-proxy-rs"
 
@@ -360,8 +359,7 @@ jobs:
 
               binary_dest = package_root / platform["binary"]
               shutil.copy2(binary_src, binary_dest)
-              if platform["os"] != "windows":
-                  binary_dest.chmod(0o755)
+              binary_dest.chmod(0o755)
               shutil.copytree(frontend_dir, web_dist, dirs_exist_ok=True)
 
               archive_name = f"{APP_NAME}_{version}_{platform['os']}_{platform['arch']}.{platform['archive']}"
@@ -369,11 +367,6 @@ jobs:
               if platform["archive"] == "tar.gz":
                   with tarfile.open(archive_path, "w:gz") as archive:
                       archive.add(package_root, arcname=APP_NAME)
-              elif platform["archive"] == "zip":
-                  with zipfile.ZipFile(archive_path, "w", zipfile.ZIP_DEFLATED) as archive:
-                      for path in sorted(package_root.rglob("*")):
-                          if path.is_file():
-                              archive.write(path, path.relative_to(package_dir))
               else:
                   raise SystemExit(f"Unsupported archive format: {platform['archive']}")
               archives.append(archive_path)