feat: use two-column diagonal diff hatching (EXPERIMENT; DISCARDED)

TODO.md

@@ -1,14 +1,13 @@
 - [x] add option to highlight trailing whitespace (off by default)
 - [x] add option to put characters at certain whitespace characters (off by default)
 	- whitespace kind -> character map should be configurable.
-- [ ] diff view - design question:
-	- is it possible to angle the hatchings for empty lines more?
-	- if a character like the current one exists with a 45degree angle instead (and a top and bottom), we could use that across two columns. that would give us a perfectly 45 degree hatching.
+- [x] diff view: use two-column diagonal hatching for missing counterparts (45° with 2:1 terminal cells)
 - [ ] github/gitlab/gitea integration (probably requries authentication with github)
 	- github pr picker (floating window)
 	- three tabs: open, closed, all
 	- search under the given category
 	- selecting a pr opens the diff viewer for that pr using the branch merge base (standard github diff view on prs; already implemented as default diff viewer behavior in vamp)
+- [ ] cut down on the amount of documentation in the project (readme file is needlessly detailed and filled with irrelevant information).
 - [ ] diff view: github integration (code review) - add comments on a pr, add review comments at specific lines of files, request changes, approve pr, etc.
 - [ ] diff view: local review comments (same features as for github reviews) that allows review of local changes to deliver specific reviews to ai agents used for coding.
     - design question: would this require a server that the agent can interact with, or would local review files be fine? don't want to use server client stuff, if it would be easier and better to just use local files.