feat: forward agent style via native CLI config and terminal title

Replace prompt-injection for display identity with native UI wiring:
- Claude: writes a statusline shell script + custom theme JSON, wired up
  via settings.json so label/color show in the status bar and theme
- Codex: writes [tui] block into codex-config.toml (status_line,
  terminal_title, dark-ansi theme)
- Both backends set the terminal title via ANSI OSC 0 escape before
  exec-ing the agent when a label is present

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bot_bottle/backend/docker/launch.py

@@ -175,6 +175,7 @@ def launch(
             None,
             agent_command=plan.agent_command,
             agent_prompt_mode=plan.agent_prompt_mode,
+            terminal_title=plan.spec.label or plan.spec.agent_name,
         )
         bottle.prompt_path = provision(plan, bottle)