refactor(ui/renderer/tests): remove trailing-border flags, filter internal messages, normalize extmarks

- Remove extend_border_to_trailing_blank from permission and question window displays.
- Filter messages with ids starting with __opencode_ before calling full-session render.
- Normalize extmark serialization (move virt_text_pos, virt_text_hide, virt_text_win_col, priority into consistent ordering) and update expected test fixtures/timestamps.
- Update unit tests to match new display options.

Author: sudo-tee

lua/opencode/ui/permission_window.lua

@@ -174,7 +174,6 @@ function M.format_display(output)
     title = icons.get('warning') .. ' Permission Required' .. progress,
     title_hl = 'OpencodePermissionTitle',
     border_hl = 'OpencodePermissionBorder',
-    extend_border_to_trailing_blank = true,
     content = render_content and nil or content,
     render_content = render_content,
     options = options,

lua/opencode/ui/question_window.lua

@@ -252,7 +252,6 @@ function M.format_display(output)
     title = icons.get('question') .. ' Question' .. progress,
     title_hl = 'OpencodeQuestionTitle',
     border_hl = 'OpencodeQuestionBorder',
-    extend_border_to_trailing_blank = true,
     content = vim.split(question_info.question, '\n'),
     options = options,
     unfocused_message = 'Focus Opencode window to answer question',

lua/opencode/ui/renderer/events.lua

@@ -383,7 +383,10 @@ function M.on_session_updated(properties)
   end
 
   if revert_changed then
-    require('opencode.ui.renderer')._render_full_session_data(state.messages)
+    local real_messages = vim.tbl_filter(function(msg)
+      return not (msg.info and msg.info.id and msg.info.id:match('^__opencode_'))
+    end, state.messages or {})
+    require('opencode.ui.renderer')._render_full_session_data(real_messages)
   end
 end