Commit file and folder drops

Pinned source: 7338078f8ddd924b8cddee35f512f2286072136d, CommitDlg.cpp::OnFileDropped, GitStatusListCtrl.cpp::ResetChecked and CGitStatusListCtrlDropTarget::OnDrop/DragOver.

The source enables ordinary file drops in Commit. Each item must belong to the same repository, receives git add -- path without force, extends a scoped list when necessary and clears that path's remembered checkbox decision. Directory checks reset descendants. A 200 ms timer batches the status refresh. The active ordinary file workflow is separate from the disabled changelist-movement code. Group headings and the list's own drag are rejected by the source.

The native changes table now accepts Finder file URLs through SwiftUI's native drop destination, without replacing its AppKit table/selection/menu behavior. Only file-URL data representations are read; no file promise, content-copy or plain-text drop is accepted. Providers retain order and URL loads have a bounded request, cancellation and once-only completion. The table probe converts drop coordinates to real rows and rejects group headings. Busy, message-only, Quit confirmation and sheet states reject drops. File URLs from another repository, nested repositories, metadata and escaping parent links are ignored. Parent aliases are resolved for repository membership; a leaf symlink is added as a link rather than reading its target. Root drops stage ..

Accepted paths use literal Git pathspecs and individual ordinary adds. Ignored files are not forced into the index, and a failed item does not stop the remaining items. The native form reports those failures instead of silently discarding the source add exit status. No disk item is copied, moved or deleted. Existing staged content for unrelated paths is retained. Git's ordinary folder/root add semantics, including embedded-repository handling, still apply.

One refresh follows the accepted batch, preserving unrelated checkbox choices, message and highlighted selection. A scoped dialog adds paths not already visible or covered by its scopes; a root drop switches to the whole project. Dropped paths and directory descendants return to the source's automatic/direct-file check rules, respecting missing/submodule defaults and ignore-on-commit membership. Staging mode uses the same add and refresh workflow.

URL reads and Git operations share the dialog's existing owned cancellation lifetime. Cancel waits for that work before settling; forced closure cancels and fences late provider or backend replies. A global count continues to guard Quit until the owned request finishes, even after its window closes. The captured repository/executable/access lease is retained. App Store mode requires the captured repository grant before resolving URLs or invoking Git; signed execution and physical Finder permission delivery remain unverified.

Full mouse-driven Finder drag acceptance, VoiceOver feedback, every alias/volume case, multi-display coordinates and signed App Store acceptance remain open. This adds an active Commit workflow; it does not certify complete Commit or application parity.

The file-drop batch passed eight Core tests and four grouped native cases across system and bundled Git. See the scoped evidence.

The membership resolver is now shared with Add. Add only refreshes its selection; Commit retains its source ordinary-add behavior.