refactor: clean up PR sudo-tee#42 based on maintainer feedback

- Remove unnecessary inline type annotations in session_formatter.lua
- Remove deprecated assistant_mode field from Message type
- Simplify mode field documentation
- Remove assistant_mode fallback logic in header formatting
- Restore accidentally deleted keymap and context config fields
- Fix indentation inconsistencies

This addresses all review feedback from @sudo-tee while preserving
the core feature: using CLI-persisted mode field to display agent
names (BUILD, PLAN, etc.) in assistant message headers.

Author: Danilo Verde Ribeiro

lua/opencode/ui/session_formatter.lua

@@ -209,10 +209,10 @@ function M._format_revert_message(stats)
       end
       if #file_diff > 0 then
         local line_str = string.format(icons.get('file') .. '%s: %s', file, table.concat(file_diff, ' '))
-        local line_idx = M.output:add_line(line_str) ---@type number
-        local col = #('  ' .. file .. ': ') ---@type number
+        local line_idx = M.output:add_line(line_str)
+        local col = #('  ' .. file .. ': ')
         for _, diff in ipairs(file_diff) do
-          local hl_group = diff:sub(1, 1) == '+' and 'OpencodeDiffAddText' or 'OpencodeDiffDeleteText' ---@type string
+          local hl_group = diff:sub(1, 1) == '+' and 'OpencodeDiffAddText' or 'OpencodeDiffDeleteText'
           M.output:add_extmark(line_idx, {
             virt_text = { { diff, hl_group } },
             virt_text_pos = 'inline',
@@ -310,15 +310,11 @@ function M._format_message_header(message, msg_idx)
   M.output:add_empty_line()
   M.output:add_metadata({ msg_idx = msg_idx, part_idx = 1, role = role, type = 'header' })
 
-  -- Use the mode field from the message (stable label from CLI)
   local display_name
   if role == 'assistant' then
     local mode = message.mode
-    -- For the most recent assistant message, show current_mode if mode is missing
-    -- This handles new messages that haven't been stamped yet
-    local is_last_message = msg_idx == #state.messages
-    if is_last_message and state.current_mode and state.current_mode ~= '' then
-      display_name = state.current_mode:upper()
+    if mode and mode ~= '' then
+      display_name = mode:upper()
     else
       display_name = 'ASSISTANT'
     end
@@ -376,7 +372,7 @@ function M._format_user_message(text, message)
     context = context_module.extract_from_opencode_message(message)
   end
 
-  local start_line = M.output:get_line_count() - 1 ---@type number
+  local start_line = M.output:get_line_count() - 1
 
   M.output:add_empty_line()
   M.output:add_lines(vim.split(context.prompt, '\n'))
@@ -394,7 +390,7 @@ function M._format_user_message(text, message)
     M.output:add_line(string.format('[%s](%s)', path, context.current_file))
   end
 
-  local end_line = M.output:get_line_count() ---@type number
+  local end_line = M.output:get_line_count()
 
   M._add_vertical_border(start_line, end_line, 'OpencodeMessageRoleUser', -3)
 end
@@ -539,10 +535,6 @@ function M._format_tool(part)
   local metadata = (part.state and part.state.metadata) or {}
   local output = (part.state and part.state.output) or ''
 
-  if state.current_permission and state.current_permission.messageID == part.messageID then
-    metadata = state.current_permission.metadata or metadata
-  end
-
   if tool == 'bash' then
     M._format_bash_tool(input --[[@as BashToolInput]], metadata --[[@as BashToolMetadata]])
   elseif tool == 'read' or tool == 'edit' or tool == 'write' then
@@ -573,7 +565,7 @@ function M._format_tool(part)
 
   M.output:add_empty_line()
 
-  local end_line = M.output:get_line_count() ---@type number
+  local end_line = M.output:get_line_count()
   if end_line - start_line > 1 then
     M._add_vertical_border(start_line, end_line - 1, 'OpencodeToolBorder', -1)
   end
@@ -602,7 +594,7 @@ function M._format_task_tool(input, metadata, output)
     end
   end
 
-  local end_line = M.output:get_line_count() ---@type number
+  local end_line = M.output:get_line_count()
   M.output:add_action({
     text = '[S]elect Child Session',
     type = 'select_child_session',