feat(clipboard): support windows (#345)

Signed-off-by: Hanchin Hsieh <me@yuchanns.xyz>

README.md

@@ -49,6 +49,8 @@ Install `avante.nvim` using [lazy.nvim](https://github.com/folke/lazy.nvim):
           drag_and_drop = {
             insert_mode = true,
           },
+          -- required for Windows users
+          use_absolute_path = true,
         },
       },
     },

lua/avante/clipboard.lua

@@ -61,14 +61,15 @@ M.get_base64_content = function(filepath)
   local output
   if os_mapping == "darwin" or os_mapping == "linux" then
     output = Utils.shell_run(("cat %s | base64 | tr -d '\n'"):format(filepath))
+  else
+    output =
+      Utils.shell_run(("([Convert]::ToBase64String([IO.File]::ReadAllBytes('%s')) -replace '`r`n')"):format(filepath))
+  end
   if output.code == 0 then
     return output.stdout
   else
     error("Failed to convert image to base64")
   end
-  else
-    Utils.warn("Windows is not supported yet", { title = "Avante" })
-  end
 end
 
 return M