Tries to create `cfg`, which collides with the seeded directory of the
same name. /files/save returns 409 "destination is not a file";
routedSaveClicked routes that through fo.askConflict, which opens the
inline #files-conflict-modal on top of the still-open routed editor.
Clicking keep-both triggers a second POST with the suffixed path
(`cfg (1)`), the routed modal closes, and the new row materialises in
the tree.
This is the F4 path from 8dc14f0 ("wire askConflict into the routed
new-file 409 path"). Before that commit, the routed code branch fell
through to a generic alert(). With this test in place, a missing
call site fails loudly instead of silently.
Pins three invariants:
* The conflict dialog is INLINE, not routed — it appears without a
URL change (the decision tree in AGENTS.md "Modals: inline vs
routed" hinges on this).
* .files-conflict-path echoes the original colliding path, not the
computed suffix — the suffix is internal, the user sees the
collision.
* withCollisionSuffix("cfg") → "cfg (1)" (no dot after the last
slash → trailing-suffix branch in uploads.js).
Per docs/superpowers/plans/2026-05-17-files-overlay-e2e-handoff.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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