Mirrors what Copilot CLI and Claude Code do: keep the terminal tab/window title in sync with the live session so users with many tabs can identify each one at a glance.

Format: 'Kimi Code [\u00b7 <topic>] [\u00b7 <cwd-basename>]'. The topic is the session's auto-generated or user-set title; it is clipped to 40 characters.

Updates are intentionally low-frequency and tied to real state changes (NOT every keystroke or token):

  - Session created / found / continued (cli/__init__.py)

  - Auto-derived topic after the first turn (soul/kimisoul.py)

  - User runs /title (ui/shell/slash.py)

Refs MoonshotAI#1475 (regression from v1.15.0 that set the title to a static 'Kimi Code'). Prior attempt MoonshotAI#1519 was closed without comment; this version uses the session topic as well as cwd, keeps the helper tested, and confines updates to well-defined hooks.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…itize OSC payload

- Route set_terminal_title through the pre-redirect stderr fd so /title and auto-topic refreshes keep working after redirect_stderr_to_logger swaps fd 2 for a pipe; cache the dup'd handle for the process lifetime to avoid os.dup + fdopen on every call. Falls back to sys.stderr only when the redirector isn't installed yet (early startup), and no-ops when no TTY is reachable so 'kimi --print' / piped runs stay quiet. (PR MoonshotAI#2083 reviews from Devin, Codex P1, Copilot)
- Sanitize the composed title via _sanitize_osc_payload at the single chokepoint inside set_terminal_title: strip C0 (0x00-0x1f), DEL (0x7f), and C1 (0x80-0x9f) so that user-influenced topic and filesystem-derived cwd basenames cannot inject ESC/BEL/CR/LF and break out of the OSC sequence. Unicode (Chinese, Japanese, emoji, accented Latin) is preserved verbatim. (Codex P2, Copilot)
- Narrow exception handlers in soul/kimisoul.py and ui/shell/slash.py from bare 'except Exception: pass' to 'except OSError' with a logger.opt(exception=True).debug carrying the session id. (Copilot)
- Add get_original_stderr_handle public helper to utils/logging.py exposing the redirector's pre-redirect fd without needing the context-manager close semantics, so the proctitle cache can hold the handle long-term.
- Tests: add coverage for the redirected-stderr fallback path, the early-startup fallback to sys.stderr, the non-TTY original-stderr no-op path, OSC control-byte sanitization, and Chinese / emoji round-trips through the OSC payload.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Two follow-ups from upstream review on PR MoonshotAI#2083:

1. The startup title refresh used 'session.state.custom_title or session.title or None', but Session.refresh() assigns the string 'Untitled' to empty sessions, so every fresh tab showed 'Kimi Code · Untitled · <cwd>'. Filter that placeholder out so the topic is omitted until a real one is generated.

2. The sys.stderr fallback in set_terminal_title only caught OSError. On legacy Windows code pages or ASCII/C locales, writing a Unicode topic (Chinese, emoji) raised UnicodeEncodeError mid-startup. Pre-encode through the stream's own encoding with errors='replace' and broaden the suppressed exceptions to (OSError, UnicodeError, LookupError) so title updates stay best-effort.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The two stderr-fallback tests set proctitle._original_stderr_attempted = True before running, but that attribute does not exist in the module — Python silently created it as a fresh attribute that nothing reads, making the reset a no-op. The autouse _reset_cached_handle fixture and the stubbed get_original_stderr_handle already provide the needed isolation, so the unused lines are dropped.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Session.create / find / continue_ canonicalize the work_dir but the startup title call still used the raw CLI 'work_dir' argument. Running 'kimi --work-dir .' (or '..') therefore produced tab titles like 'Kimi Code . .' instead of 'Kimi Code . my-project', regressing the multi-tab disambiguation that motivates this feature for relative --work-dir usage.

Switching to 'session.work_dir' (already canonicalized) gives the actual project basename in every entry path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>