Opens server.cfg through the file-row name button, drives the CM6
controller via window.__filesEditor.setContent, clicks save, and
asserts both that the routed modal closes and that the new bytes
landed on disk under overlay_root. Guards against four classes of
regression at once: the /files/edit fragment delivering the wrong
data-rel-path, editor.js's htmx:afterSwap re-init failing to wire
__filesEditor, routedSaveClicked stopping short of closeRouted(),
and the /files/save endpoint failing to persist.
Adds a `_wait_for_routed_editor` helper centered on `.cm-content`
inside `#files-editor-fragment` — the textarea itself is
display:none after CM6 mounts, so to_be_visible on the textarea
would always fail; the cm-content surface is the real "editor is
ready" signal.
Per docs/superpowers/plans/2026-05-17-files-overlay-e2e-handoff.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
