feat(profiler/behave_shell): emit temporal.lifecycle_markers.exit_behavior

Resolves the E.4 hold from Phase E. F.0's Command.followed_by_prompt
gives us the exit-code proxy (prompt-after-last-command) we couldn't
get in Phase E.

Logic: last command without trailing prompt → abrupt; first_token_hash
in {exit, logout, quit, logoff} → graceful; any of the last K=3
commands' first_token_hash in {history, unset, rm, shred, clear, kill}
→ cleanup; else → graceful (clean Ctrl-D / window close).

tests/profiler/behave_shell/test_temporal_exit_behavior.py

@@ -0,0 +1,79 @@
+"""Step E.4: ``temporal.lifecycle_markers.exit_behavior`` (unblocked by F.0)."""
+from __future__ import annotations
+
+from decnet.profiler.behave_shell import extract_session
+from decnet.profiler.behave_shell._parse import AsciinemaEvent
+
+
+PRIMITIVE = "temporal.lifecycle_markers.exit_behavior"
+
+
+def _of(observations: list, primitive: str):
+    obs = [o for o in observations if o.primitive == primitive]
+    assert len(obs) == 1, f"expected exactly one {primitive}, got {len(obs)}"
+    return obs[0]
+
+
+def _typed(text: str, t0: float = 0.0, dt: float = 0.05) -> list[AsciinemaEvent]:
+    return [(t0 + i * dt, "i", c) for i, c in enumerate(text)]
+
+
+def _cmd(token: str, t0: float, *, with_prompt: bool = True) -> list[AsciinemaEvent]:
+    """Emit one command + (optionally) a trailing prompt-line."""
+    events = _typed(f"{token}\r", t0=t0)
+    cmd_end = t0 + len(token) * 0.05
+    if with_prompt:
+        events.append((cmd_end + 0.10, "o", "out\nanti@host:~$ "))
+    else:
+        events.append((cmd_end + 0.10, "o", "out\n"))
+    return events
+
+
+def test_no_commands_no_emission() -> None:
+    out = list(extract_session([(0.0, "i", "x")], sid="ex-empty"))
+    assert [o for o in out if o.primitive == PRIMITIVE] == []
+
+
+def test_last_command_no_prompt_emits_abrupt() -> None:
+    """Session cut mid-output → no trailing prompt → abrupt."""
+    events = _cmd("ls", t0=0.0) + _cmd("foo", t0=1.0, with_prompt=False)
+    obs = _of(list(extract_session(events, sid="ex-abrupt")), PRIMITIVE)
+    assert obs.value == "abrupt"
+
+
+def test_explicit_exit_token_emits_graceful() -> None:
+    events = _cmd("ls", t0=0.0) + _cmd("exit", t0=1.0)
+    obs = _of(list(extract_session(events, sid="ex-graceful")), PRIMITIVE)
+    assert obs.value == "graceful"
+
+
+def test_logout_token_emits_graceful() -> None:
+    events = _cmd("ls", t0=0.0) + _cmd("logout", t0=1.0)
+    obs = _of(list(extract_session(events, sid="ex-logout")), PRIMITIVE)
+    assert obs.value == "graceful"
+
+
+def test_cleanup_token_in_tail_emits_cleanup() -> None:
+    """Last few commands include cleanup vocabulary → cleanup."""
+    events = (
+        _cmd("ls", t0=0.0)
+        + _cmd("cat", t0=1.0)
+        + _cmd("history", t0=2.0)  # cleanup-family token in tail
+    )
+    obs = _of(list(extract_session(events, sid="ex-cleanup")), PRIMITIVE)
+    assert obs.value == "cleanup"
+
+
+def test_clean_session_with_prompt_emits_graceful() -> None:
+    """Trailing prompt + no exit/cleanup tokens → graceful (Ctrl-D path)."""
+    events = _cmd("ls", t0=0.0) + _cmd("ps", t0=1.0) + _cmd("cat", t0=2.0)
+    obs = _of(list(extract_session(events, sid="ex-clean")), PRIMITIVE)
+    assert obs.value == "graceful"
+
+
+def test_abrupt_lower_confidence_than_graceful() -> None:
+    abrupt_events = _cmd("ls", t0=0.0) + _cmd("foo", t0=1.0, with_prompt=False)
+    graceful_events = _cmd("ls", t0=0.0) + _cmd("exit", t0=1.0)
+    a = _of(list(extract_session(abrupt_events, sid="ex-a")), PRIMITIVE)
+    g = _of(list(extract_session(graceful_events, sid="ex-g")), PRIMITIVE)
+    assert a.confidence < g.confidence