Feature: Container-aware update guidance

  As the owner of a RenewCMS site running in Docker
  I want Settings to say "update by pulling a new image" instead of "Not prepared"
  So that I never see a browser-update flow that cannot work in a container

  Background:
    Given browser updates need Linux with systemd and the helper that "renewcms enable-browser-updates" configures
    And a binary replaced inside a container is lost when the container is recreated,
      so in a container the update is a new image: "docker compose pull && docker compose up -d"
    And config.Settings gains Container bool, read from the env var RENEWCMS_CONTAINER (default "false", set to "true" by the Dockerfile and docker-compose.yml)
    And RENEWCMS_CONTAINER is added to envDefaults in cmd/server/main.go, to .env.example and to docs/configuration.md; it is not in requiredEnvVars
    And only "true" (case-insensitive) enables container mode; any other value means false
    And the update status use case receives the bool through its constructor from api/dependecyInjection.go; internal/domain/update stays stdlib only
    And the update check, update-status.json and the release feed work unchanged in container mode
    And GET /v1/system/update gains a 13th key, container (bool), after started_at; the other 12 keys are unchanged
    And in container mode can_apply is false for everyone, even if update-helper.json exists in the data directory
    And POST /v1/system/update/download and /restart keep their guards and answer 409 because can_apply is false (existing behaviour, not re-specified)
    And errors stay plain text from http.Error
    And the user approved the copy below and the 13th key on 2026-10-05; docs/design is read-only for agents, so the design files are updated by the user, and the visual gate for container states stays PENDING until a board frame exists

  Scenario Outline: The status carries the container flag
    Given RENEWCMS_CONTAINER is "<value>"
    When a verified user sends GET /v1/system/update
    Then the JSON key container is <flag>

    Examples:
      | value | flag  |
      | true  | true  |
      | TRUE  | true  |
      | false | false |
      |       | false |
      | yes   | false |

  Scenario: Container mode disables apply even with a helper
    Given RENEWCMS_CONTAINER is "true" and HelperDetector reports the helper installed
    When the owner sends GET /v1/system/update
    Then can_apply is false and container is true
    And a newer stored result still reports available true, latest and notes

  Scenario: The check still works in a container
    Given container mode and a feed that reports "v2.9.0-beta" newer than the running "v2.8.0-beta"
    When the owner sends POST /v1/system/update/check
    Then the status is 200 and available is true and the result is stored in update-status.json

  Scenario Outline: Download and restart are refused in a container
    Given container mode and a stored newer release
    When the owner sends POST <path>
    Then the status is 409 and no job starts and the fetcher and the restart request writer are not called

    Examples:
      | path                        |
      | /v1/system/update/download  |
      | /v1/system/update/restart   |

  Scenario: Host installs are unchanged
    Given RENEWCMS_CONTAINER is unset
    Then container is false and can_apply follows the helper as before
    And "Not prepared" still shows its "renewcms enable-browser-updates" command

  Scenario: Settings, owner, container, update available (route /settings)
    Given GET /v1/system/update resolves available true, container true, can_apply false, latest "v2.9.0-beta"
    Then the block uses the "Not prepared" frame's layout: icon info, tone info
    And the title reads "Version 2.9.0-beta is available"
    And the text reads "You have v2.8.0-beta. This site runs in Docker, so it updates by pulling a new image. Run the commands below on the server."
    And a server-command block reads "docker compose pull && docker compose up -d" with the Copy button ("Copied" with a check for 2 s, announced)
    And a link "How to update" with arrow-up-right points to docs/docker.md
    And no Update, Restart or "Check for updates" button is rendered
    And the "renewcms enable-browser-updates" command and its note are not rendered

  Scenario: Settings, owner, container, up to date
    Given container true and available false
    Then "You're up to date" shows as in the existing Up to date state, the Restart button is not rendered and the container hint is not rendered
    And "Check for updates" is still offered

  Scenario: Settings, admin, container
    Given the session role is "admin", container true and available true
    Then the existing Admin view shows unchanged ("Only the owner can update RenewCMS.") with no command block

  Scenario: Settings, non-container, no helper
    Given container false and can_apply false
    Then the existing "Not prepared" state shows unchanged

  Scenario: The shipped Docker setup turns container mode on
    Given the Dockerfile and docker-compose.yml
    Then both set RENEWCMS_CONTAINER=true
    And docs/docker.md and docs/configuration.md describe the variable