feat(picker.util): cmdline parser used to properly parse diff args

lua/snacks/picker/util/init.lua

@@ -646,4 +646,53 @@ function M.globber(globs)
   end
 end
 
+---@param cmdline string
+---@return string[]
+function M.parse_cmdline(cmdline)
+  local args = {} ---@type string[]
+  local current = ""
+  local in_quote = false
+  local quote_char = nil
+  local i = 1
+
+  while i <= #cmdline do
+    local char = cmdline:sub(i, i)
+    local next_char = cmdline:sub(i + 1, i + 1)
+
+    if char == "\\" and next_char ~= "" then
+      -- Escaped character - take next char literally
+      current = current .. next_char
+      i = i + 2
+    elseif not in_quote and (char == '"' or char == "'") then
+      -- Start quote
+      in_quote = true
+      quote_char = char
+      i = i + 1
+    elseif in_quote and char == quote_char then
+      -- End quote
+      in_quote = false
+      quote_char = nil
+      i = i + 1
+    elseif not in_quote and char:match("%s") then
+      -- Whitespace outside quotes - split arg
+      if current ~= "" then
+        args[#args + 1] = current
+        current = ""
+      end
+      i = i + 1
+    else
+      -- Regular character or whitespace inside quotes
+      current = current .. char
+      i = i + 1
+    end
+  end
+
+  -- Add last arg if any
+  if current ~= "" then
+    args[#args + 1] = current
+  end
+
+  return args
+end
+
 return M