feat: dim whitespace markers and configure scope and newlines

docs/configuration.md

@@ -17,7 +17,8 @@ Vamp.configure do |config|
   config.git_gutter = "bar" # or "symbols", "line_numbers", "none"
   config.scroll_distance = 0 # nonnegative edge distance, or nil to center
   config.highlight_trailing_whitespace = false # true marks line-end whitespace in red
-  config.whitespace_characters = {} # opt in: { " " => "·", "\t" => "→", "\u00a0" => "⍽" }
+  config.whitespace_characters = {} # opt in: { " " => "·", "\t" => "→", "\n" => "↵" }
+  config.whitespace_scope = "all" # or "leading" for indentation only
   config.file_explorer_side = "right"
   config.file_explorer_view = "tree"
   config.file_picker_view = "tree"
@@ -56,11 +57,15 @@ The setting applies to ordinary and historical buffers, split/unified diff panes
 
 `config.highlight_trailing_whitespace` defaults to `false`. Set it to `true` to give trailing whitespace a red background in ordinary and historical buffers and both sides of split/unified diffs, including wrapped and horizontally scrolled text. Spaces, expanded tab cells, and Unicode whitespace at the end of a source line are highlighted; whitespace-only lines are included, but empty lines and padding beyond the text are not. Wrapping does not make interior whitespace trailing. Search, selections, and secondary carets retain their background precedence; diagnostic underlines remain visible. This changes display only, not file contents. Only literal Ruby booleans are accepted; other values reject the configuration.
 
-`config.whitespace_characters` defaults to `{}` (disabled). Assign a hash mapping literal whitespace characters to display markers, for example `{ " " => "·", "\t" => "→", "\u00a0" => "⍽" }` for spaces, tabs, and nonbreaking spaces. Unlisted characters keep their ordinary appearance. Keys and values must be single-character strings; keys must be whitespace with visible terminal width, or tabs, and values must be printable one-cell characters. Line breaks and other control characters, zero-width markers, and wide markers reject the configuration.
+`config.whitespace_characters` defaults to `{}` (disabled). Assign a hash mapping literal whitespace characters to dim display markers, for example `{ " " => "·", "\t" => "→", "\u00a0" => "⍽", "\n" => "↵" }` for spaces, tabs, nonbreaking spaces, and line breaks. Unlisted characters keep their ordinary appearance. Keys and values must be single-character strings; keys must be whitespace with visible terminal width, tabs, or `"\n"`, and values must be printable one-cell characters. Carriage returns and other control characters, zero-width markers, and wide markers reject the configuration. Only indicator cells receive terminal dim styling; source-text colors, diagnostic underlines, and highlighted backgrounds remain intact.
+
+`config.whitespace_scope` defaults to `"all"`. Use `"leading"` to mark only the initial whitespace prefix of each source line; a whitespace-only line is entirely leading, but wrapping and horizontal scrolling do not create new indentation. Only the strings `"all"` and `"leading"` are accepted; other values reject the configuration.
+
+A `"\n"` map entry marks actual line breaks independently of `whitespace_scope`, including blank lines and a file's final newline when present. Soft wraps, missing final newlines, and the virtual empty EOF row do not gain markers. The glyph occupies the existing end-of-line caret cell on the final wrapped segment; a full-width line uses the existing extra caret segment. In unwrapped text, an offscreen end-of-line marker is clipped like other source cells. Newline markers inside syntax-recognized strings are suppressed along with horizontal whitespace markers.
 
 Whitespace inside strings recognized by the bundled syntax grammar stays literal, including raw/multiline strings, heredocs, interpolated strings, and strings with embedded-language highlighting. Outside strings, configured markers still apply. String boundaries come from the original source, so wrapping, horizontal scrolling, and split/unified historical diffs retain this distinction. Plain text and unknown languages have no syntax-defined string boundaries; quotes are not guessed to be strings.
 
-Markers appear in ordinary and historical buffers and both sides of split/unified diffs. Tabs and wide Unicode whitespace show the marker in their first source cell and leave remaining cells blank, preserving tab stops, wrapping, horizontal scrolling, and cursor/selection geometry. A clipped first cell hides its marker; empty lines and padding do not gain markers. Whitespace with combining characters remains intact. Syntax colors, search, selections, diagnostics, and trailing-whitespace highlighting still apply. This changes display only: editing, copying, and saving retain the original characters.
+Markers appear in ordinary and historical buffers and both sides of split/unified diffs. Tabs and wide Unicode whitespace show the marker in their first source cell and leave remaining cells blank, preserving tab stops, wrapping, horizontal scrolling, and cursor/selection geometry. A clipped first cell hides its marker; padding beyond the source does not gain markers. Whitespace with combining characters remains intact. Syntax colors, search, selections, diagnostics, and trailing-whitespace highlighting still apply. This changes display only: editing, copying, and saving retain the original characters.
 
 `config.git_blame` defaults to `true`; set it to `false` to disable current-line inline Git blame and its background worker. Only literal Ruby booleans are accepted; other values reject the configuration. Toggle it for the running session with `:git_blame.toggle`, its palette action, or a custom binding such as `config.bind "leader b", config.core.git_blame.toggle`. There is no default shortcut.