fix(init): load oil buffer when BufAdd hijack fires under trouble/bqf

Problem: `BufAdd` handler renames a directory buffer to its `oil://`
URL and relies on the resulting `BufReadCmd` to load it. Plugins like
trouble.nvim that intercept quickfix opening suppress nested autocmds,
so `BufReadCmd` never fires and the buffer is left blank.

Solution: call `load_oil_buffer` directly after a successful hijack,
matching the startup loop which already does this. `load_oil_buffer`
guards against double-loading, so normal-path callers where
`BufReadCmd` does fire are unaffected.

lua/oil/init.lua

@@ -1646,7 +1646,9 @@ M.setup = function(opts)
       pattern = '*',
       nested = true,
       callback = function(params)
-        maybe_hijack_directory_buffer(params.buf)
+        if maybe_hijack_directory_buffer(params.buf) and vim.v.vim_did_enter == 1 then
+          M.load_oil_buffer(params.buf)
+        end
       end,
     })