fix(tui): refresh footer on collaboration mode changes (#16026)

## Summary
- Moves status surface refresh (`refresh_status_surfaces` /
`refresh_status_line`) from `App` event handlers into `ChatWidget`
setters via a new `refresh_model_dependent_surfaces()` method
- Ensures model-dependent UI stays in sync whenever collaboration mode,
model, or reasoning effort changes, including the footer and terminal
title in both `tui` and `tui_app_server`
- Applies the fix to both `tui` and `tui_app_server` widgets

#15961

## Test plan
- [x] Added snapshot test
`status_line_model_with_reasoning_plan_mode_footer` verifying footer
renders correctly in plan mode
- [x] Added
`terminal_title_model_updates_on_model_change_without_manual_refresh` in
`tui_app_server`
- [ ] Verify switching collaboration modes updates the footer in real
TUI
- [ ] Verify model/reasoning effort changes reflect in the status bar
and terminal title

---------

Co-authored-by: Eric Traut <etraut@openai.com>

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__mcp_tools_output_lists_tools_for_hyphenated_server_names.snap

@@ -1,16 +0,0 @@
----
-source: tui/src/history_cell.rs
-assertion_line: 3080
-expression: rendered
----
-/mcp
-
-🔌  MCP Tools
-
-  • some-server
-    • Status: enabled
-    • Auth: Unsupported
-    • Command: docs-server --stdio
-    • Tools: lookup
-    • Resources: (none)
-    • Resource templates: (none)