Play Framework

chore: rename CLI command 'play auto-test' to 'play autotest' (PF-90)

The Gradle task is playAutotest (single word). The hyphenated CLI
form auto-test was a Python-era artifact — the underlying source
file was always pym/play/commands/autotest.py and the doc page
already listed autotest as an alias. In 1.13 we promote the alias
to canonical and drop the hyphenated form.

- play wrapper: auto-test -> autotest in both the help text and
  the task lookup case statement. No backward-compat alias kept;
  'play auto-test' will now print 'unknown command'.
- Renames documentation/commands/cmd-auto-test.txt -> cmd-autotest.txt
  and removes the now-defunct 'Alias: autotest' section in its body.
- Updates AGENTS.md, CLAUDE.md, SECURITY.md, both cheatsheets,
  manual + manual_ja (configuration / modules / test pages), and the
  Play1Plugin.kt comment that documents ensureTestSecret's purpose.

Historical references in documentation/manual/releases/* and
support/{play_completion,zsh/_play} are left alone — release notes
should reflect the names as they shipped, and the support/ shell-
completion files are stale Python-CLI artifacts that need their own
sweep.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>