feat(git): add in-house hunks module, replace gitsigns.nvim

lua/git/status_view.lua

@@ -1,5 +1,5 @@
 local Revision = require("git.core.revision")
-local diff = require("git.diff")
+local diffsplit = require("git.diffsplit")
 local object = require("git.object")
 local repo = require("git.core.repo")
 local status = require("git.core.status")
@@ -399,7 +399,7 @@ local function view_row(s, row, focus_left)
     local older = left.name or vim.api.nvim_buf_get_name(left.buf)
     local left_win
     vim.api.nvim_win_call(target, function()
-        diff.split({
+        diffsplit.open({
             target = older,
             mods = { vertical = true },
         })