refactor(#2871, #2886): multi instance: node classes created (#2916)

* refactor(#2875): multi instance renderer

* refactor(#2875): multi instance renderer

* refactor(#2875): multi instance renderer

* refactor(#2875): multi instance renderer

* node classes and constructors

* node methods

* refactor(#2875): multi instance renderer

* node classes and constructors

* explorer is a directory node

* extract methods from explore_node

* extract methods from explore_node

* extract methods from explore_node

* extract methods from lib

* use .. name for root node for compatibility

* use node.explorer

* extract node factory, remove unused code

* factories for all nodes, add RootNode

* factories for all nodes, add RootNode

* use factory pattern for decorators

* note regression and commit

* fix dir git status regression

* destroy nodes, not explorer

* add BaseNode:is

* revert changes to create-file, handle in #2924

* extract methods from explorer

* extract methods from explorer

* extract methods from explorer

* use Node everywhere in luadoc

* extract methods from lib

* extract methods from lib

* lint

* remove unused code

* don't call methods on fake root node

* get_node_at_cursor returns explorer (root) node instead of { name = '..' }

* remove unused inject_node

* refactor(#2875): multi instance renderer

* refactor(#2875): multi instance renderer

* refactor(#2875): multi instance renderer

* extract methods from lib

* node factory uses stat only

* temporary DirectoryNode casting until method extraction into child classes

* lua-language-server 3.10.5 -> 3.11.0

* explicitly call Explorer constructor

* normalise explorer RootNode new call, tidy annotations

lua/nvim-tree/node/file.lua

@@ -0,0 +1,49 @@
+local utils = require("nvim-tree.utils")
+
+local BaseNode = require("nvim-tree.node")
+
+---@class (exact) FileNode: BaseNode
+---@field extension string
+local FileNode = BaseNode:new()
+
+---Static factory method
+---@param explorer Explorer
+---@param parent Node
+---@param absolute_path string
+---@param name string
+---@param fs_stat uv.fs_stat.result?
+---@return FileNode
+function FileNode:create(explorer, parent, absolute_path, name, fs_stat)
+  ---@type FileNode
+  local o = {
+    type = "file",
+    explorer = explorer,
+    absolute_path = absolute_path,
+    executable = utils.is_executable(absolute_path),
+    fs_stat = fs_stat,
+    git_status = nil,
+    hidden = false,
+    is_dot = false,
+    name = name,
+    parent = parent,
+    watcher = nil,
+    diag_status = nil,
+
+    extension = string.match(name, ".?[^.]+%.(.*)") or "",
+  }
+  o = self:new(o) --[[@as FileNode]]
+
+  return o
+end
+
+---Create a sanitized partial copy of a node, populating children recursively.
+---@return FileNode cloned
+function FileNode:clone()
+  local clone = BaseNode.clone(self) --[[@as FileNode]]
+
+  clone.extension = self.extension
+
+  return clone
+end
+
+return FileNode