* fix(native-chat): scope composer file drops to the pane that received them
A native OS file drop resolving to `target: 'composer'` carried no pane
identity, so the window-wide payload was attached by every mounted composer.
Because inactive chat tabs stay mounted (hidden), one drop populated every
chat pane's attachment cache, and those chips replayed whenever the user
returned to a tab they never dropped into. The workspace-creation composer
and chat composers also leaked into each other, since neither could tell
which surface actually received the drop.
Composer drops now carry a `scopeKey` the way a terminal drop carries its
tab and pane leaf id: the composer publishes its pane key as
`data-composer-scope-key`, the preload harvests it during the composedPath
walk, and each composer attaches only its own. The workspace composer's
last-wins ownership stack now claims unscoped payloads only.
* test(native-chat): supersede the bug-asserting drop repro with the scoping test
The repro that landed on main asserts the pre-fix behavior (a drop reaching
every mounted composer), so it fails once drops are scoped to the pane that
received them. Its scoping cases now live in
native-chat-composer-drop-scope.test.tsx, which keeps its editor-target
control case verbatim and adds coverage for unscoped composers and a scope
key published inside the drop-target marker.
* test(native-chat): cover workspace composer drop isolation
* fix(native-chat): authorize external attachment paths before preview
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Co-authored-by: Merge Sim <sim@local>
Brennan BensonandMerge Sim
Neil