fix(file_history): pin_local-safe Diff1/Diff1Inline for layout cycling

[dlyongemallo]

No description provided.

[Copilot]

Pull request overview

Extends file-history pin_local safety to single-pane Diff1/Diff1Inline layouts by introducing pinned siblings (Diff1Pinned, Diff1InlinePinned) that declare shared_symbols = { "b" } and inherit the swap-aware detach semantics from the existing Diff2 pinned variants. The view's get_default_layout / resolve_pinned_layout / unpinned_layout now route Diff1 names through these pinned forms so cycle_layout and set_layout keep the cycle reachable without dropping the view-owned working-tree file. Fixes a regression where a Diff1 entry in cycle_layouts.default caused cycling to stall on the default Diff2 orientation under pin_local.

Changes:

• Add Diff1Pinned and Diff1InlinePinned classes with shared_symbols = { "b" } and detach_files_for_swap mirroring Diff2*Pinned.
• Wire the new layouts into config.layout_map / LayoutName and into FileHistoryView's pinned_variant / unpinned_variant tables, simplifying the pinned-vs-unpinned resolution paths.
• Switch Diff1Inline:owned_files to defer to Layout:owned_files (so subclass shared_symbols is honoured) and add unit/regression tests covering Diff1 pinned ownership, swap detach, cycling, and pinned-name fallbacks.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
lua/diffview/scene/layouts/diff_1_pinned.lua	New pinned Diff1 layout with shared b-side and swap-aware detach.
lua/diffview/scene/layouts/diff_1_inline_pinned.lua	New pinned Diff1Inline layout; borrows detach_files_for_swap from Diff1Pinned.
lua/diffview/scene/layouts/diff_1_inline.lua	owned_files now delegates to Layout.owned_files so subclass shared_symbols is respected.
lua/diffview/scene/views/file_history/file_history_view.lua	Add Diff1 entries to pinned_variant; simplify get_default_layout / resolve_pinned_layout fallback logic; updated docstrings.
lua/diffview/config.lua	Register new pinned Diff1 names in LayoutName alias and layout_map; updated comment about pinned variants being internal.
lua/diffview/tests/functional/layouts_spec.lua	New tests for Diff1*Pinned owned_files and detach_files_for_swap behaviour.
lua/diffview/tests/functional/pin_local_spec.lua	Updated get_default_layout/resolve_pinned_layout/unpinned_layout tests for Diff1 pinned routing.
lua/diffview/tests/functional/cycle_layouts_spec.lua	New regression tests covering pin_local cycling with Diff1 entries and pin_local on/off symmetry.

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