refactor: drop nvim-0.9 version checks in float title logic

Problem: the float title was only shown via the native `nvim_win_set_config`
path, which requires a border to render. The guard `config.float.border ~=
'none'` did not account for `nil`, which is the default — so users with no
explicit `border` config never saw the path title in the floating window.

Solution: require both `~= nil` and `~= 'none'` before using the native
title. In all other cases (border nil, 'none', or nvim < 0.9), fall back to
`util.add_title_to_win`, which renders a child floating window for the title.

Based on: stevearc/oil.nvim#683

doc/upstream.md

@@ -148,7 +148,7 @@ Bugs fixed in this fork that remain open upstream.
 | [#678](https://github.com/stevearc/oil.nvim/issues/678) | tracking       | `buftype='acwrite'` causes `mksession` to skip oil windows                                                                                                               |
 | [#679](https://github.com/stevearc/oil.nvim/issues/679) | resolved       | Executable file sign — PR [#698](https://github.com/stevearc/oil.nvim/pull/698)                                                                                          |
 | [#682](https://github.com/stevearc/oil.nvim/issues/682) | open           | `get_current_dir()` nil in non-telescope context                                                                                                                         |
-| [#683](https://github.com/stevearc/oil.nvim/issues/683) | open           | Path not shown in floating mode                                                                                                                                          |
+| [#683](https://github.com/stevearc/oil.nvim/issues/683) | fixed          | Path not shown in floating mode — title shown via fallback when border is nil                                                                                            |
 | [#684](https://github.com/stevearc/oil.nvim/issues/684) | open           | User and group columns                                                                                                                                                   |
 | [#685](https://github.com/stevearc/oil.nvim/issues/685) | open           | Plain directory paths in buffer names                                                                                                                                    |
 | [#690](https://github.com/stevearc/oil.nvim/issues/690) | resolved       | `OilFileIcon` highlight group — [`ce64ae1`](https://github.com/barrettruth/canola.nvim/commit/ce64ae1)                                                                   |

lua/canola/init.lua

@@ -305,8 +305,7 @@ M.open_float = function(dir, opts, cb)
           vim.api.nvim_set_option_value(k, v, { scope = 'local', win = winid })
         end
 
-        -- Update the floating window title
+        if config.float.border ~= nil and config.float.border ~= 'none' then
-        if vim.fn.has('nvim-0.9') == 1 and config.float.border ~= 'none' then
           local cur_win_opts = vim.api.nvim_win_get_config(winid)
           vim.api.nvim_win_set_config(winid, {
             relative = 'editor',
@@ -316,6 +315,8 @@ M.open_float = function(dir, opts, cb)
             height = cur_win_opts.height,
             title = util.get_title(winid),
           })
+        else
+          util.add_title_to_win(winid)
         end
       end,
     })
@@ -335,7 +336,7 @@ M.open_float = function(dir, opts, cb)
     end
   end)
 
-  if vim.fn.has('nvim-0.9') == 0 then
+  if config.float.border == nil or config.float.border == 'none' then
     util.add_title_to_win(winid)
   end
 end