One-pane context commands

Baseline: 7338078f8ddd924b8cddee35f512f2286072136d. The audit covers LeftView.cpp::AddContextItems, BaseView.cpp::OnContextMenu/AddCutCopyAndPaste/UseViewBlock, RightView.cpp::UseLeftBlock/UseLeftFile, and the one-pane LoadViews branch.

A combined viewer is the source left view, even though its editable output is Mine. Its context menu now uses the left-role Use this block/file labels and does not expose the right-view Mark/Unmark/Leave only marked commands. Copy/Cut/Paste precede writable whitespace/line-ending/encoding choices in combined mode. Read-only combined views show Copy and omit Cut/Paste and format mutation commands. Encoding items follow the source's nine-choice order and carry explicit format identities, so reordering cannot dispatch the wrong enum.

Upstream still appends transfer items in the combined left view, but the handlers address the hidden right view whose data/working file are cleared by LoadViews. The Mac page disables these two-view commands rather than executing them against Mine. Block/file transfer and mark handlers reject combined mode at the model layer too, including stale menu dispatch. Toolbar transfer actions use the same gate. This corrects the earlier generic right-pane menu behavior, which could replace Mine with Base from a combined list.

Each menu retains a clipboard command target capturing its own pasteboard and a weak editor. Copy includes selected removed payload. Cut/Paste operate in Mine coordinates using the existing combined editing/Undo transaction. Opening a newer menu does not change an older menu's clipboard destination. Keyboard Copy still uses the normal system pasteboard. Closed/retired editors and busy or sheet-owned contexts refuse clipboard commands; retired models no longer allow editing or transfer dispatch.

The native receiver uses private named pasteboards, real menu dispatch and actual editor transactions. It checks removed-row copying, cross-menu captured clipboard identity, Cut/Paste and Undo, source format order/action identity, read-only command omission, hidden-opposite no-ops, late retirement, and saved inputs unchanged. The complete grouped Merge receiver retains all previous families.

Remaining: physical popup anchoring/focus/keyboard/VoiceOver acceptance, source row-state and selection aliases, exact full menu contents/spacing and light/dark captures. Mac navigation/Save As/Undo/Redo additions remain alongside the source commands. The October 16 in-place editing continuation adds Edited-row retention for typing and ordinary clipboard edits. Signed/minimum-OS acceptance remains open. No full TortoiseMerge certification is claimed.

Evidence

Unsigned Debug builds passed. One fixture frontend linked the existing app objects; all fourteen Merge receiver families passed in one owned process. No Core suite was rerun for the native-only menu changes. The check touched only private named pasteboards and scratch files. See the batch record. Hosted CI and physical/signed acceptance remain unproven.