feat(cli): show project name in session-manager window title

[jongracecox]

Summary

The session-manager TUI window title was hard-coded to 🧙🏽‍♂️ fujimoto. It now shows the project name — the same format used when a Claude session is attached, minus the worktree portion.

Details

• Added _session_manager_title(project) in cli.py, which renders 🧙🏽‍♂️ fujimoto - {project} (falls back to the bare 🧙🏽‍♂️ fujimoto prefix when no project is known).
• Called from _init_git_info, where sub_title is already set. Since _init_git_info runs on mount and on project switch, the window title correctly follows the active project through the project switcher.
• FUJIMOTO_WINDOW_TITLE deliberately does not affect the TUI title — the request was specifically for the project name without the worktree portion, so the TUI uses the fixed fujimoto - {project} form rather than the worktree-oriented template.
• set_terminal_title now writes to sys.__stdout__ instead of sys.stdout. Textual redirects sys.stdout to an internal capture while the app is running, so the OSC title escape written from _init_git_info never reached the real terminal (iTerm2). sys.__stdout__ stays connected to the tty, so the write lands both before and during app.run(). Falls back to sys.stdout when the original stream is unavailable.
• Added TestSessionManagerTitle and terminal-title tests covering the project, empty-project, and sys.__stdout__ fallback cases.
• Updated CLAUDE.md and README.md to document the TUI-screen title behavior and the sys.__stdout__ gotcha.

Full test suite passes.