feat (file_selector): Add multi select (#971)

* Add multi select

* Remove comment

lua/avante/file_selector.lua

@@ -163,6 +163,7 @@ function FileSelector:telescope_ui(handler)
   local conf = require("telescope.config").values
   local actions = require("telescope.actions")
   local action_state = require("telescope.actions.state")
+  local action_utils = require("telescope.actions.utils")
 
   pickers
     .new(
@@ -176,9 +177,21 @@ function FileSelector:telescope_ui(handler)
           map("i", "<esc>", require("telescope.actions").close)
 
           actions.select_default:replace(function()
-            actions.close(prompt_bufnr)
+            local picker = action_state.get_current_picker(prompt_bufnr)
+
+            if #picker:get_multi_selection() ~= 0 then
+              local selections = {}
+
+              action_utils.map_selections(prompt_bufnr, function(selection) table.insert(selections, selection[1]) end)
+
+              if #selections > 0 then handler(selections) end
+            else
               local selection = action_state.get_selected_entry()
+
               handler(selection[1])
+            end
+
+            actions.close(prompt_bufnr)
           end)
           return true
         end,
@@ -202,20 +215,24 @@ end
 
 ---@return nil
 function FileSelector:show_select_ui()
-  local handler = function(filepath)
+  local handler = function(filepaths)
-    if not filepath then return end
+    if not filepaths then return end
+    -- Convert single filepath to array for unified handling
+    local paths = type(filepaths) == "string" and { filepaths } or filepaths
+
+    for _, filepath in ipairs(paths) do
       local uniform_path = Utils.uniform_path(filepath)
       if Config.file_selector.provider == "native" then
-      -- Native handler filters out already selected files
         table.insert(self.selected_filepaths, uniform_path)
-      self:emit("update")
       else
         if not vim.tbl_contains(self.selected_filepaths, uniform_path) then
           table.insert(self.selected_filepaths, uniform_path)
+        end
+      end
+    end
+
     self:emit("update")
   end
-    end
-  end
 
   vim.schedule(function()
     if Config.file_selector.provider == "native" then