feat(panel): add mark_placement option for selection marks location

[dlyongemallo]

Relates to #70 (comment).

[Copilot]

Pull request overview

Adds a new file_panel.mark_placement configuration option to control whether selection marks are rendered inline (current behavior) or placed in the sign column to avoid text alignment shifts in the file panel.

Changes:

• Introduces file_panel.mark_placement = "inline" | "sign_column" with documentation and default config updates.
• Updates diff view panel rendering to suppress inline marks in sign_column mode and instead place selection marks via sign extmarks.
• Adds functional tests covering config persistence and sign-column mark behavior for file entries.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
lua/diffview/ui/panel.lua	Uses :redraw() on WinResized to ensure post-render steps run on resize.
lua/diffview/scene/views/diff/render.lua	Implements mark_placement handling and sign-column extmark placement for selection marks.
lua/diffview/scene/views/diff/file_panel.lua	Overrides :redraw() to place selection signs after buffer render.
lua/diffview/config.lua	Adds the file_panel.mark_placement default.
doc/diffview.txt	Documents the new mark_placement option.
doc/diffview_defaults.txt	Updates defaults listing to include mark_placement.
lua/diffview/tests/functional/panel_render_spec.lua	Adds functional tests for inline vs sign-column selection mark rendering.
lua/diffview/tests/functional/config_options_spec.lua	Adds config option tests for mark_placement default and persistence.

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[Copilot]

Pull request overview

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

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[jakubbortlik]

Hi David, I've tested the configuration and it works very well. The only thing is that when I use a wide character, it gets crammed very tight to the modification letter so that it makes some of the letters a little difficult to read:

It would be nice if there was a little padding, but if that would be anything more than trivial to implement, then just forget it -- it's usable and useful as it is. Thanks!

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.

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