fix(daemon): ignore idle clean exits for attention

[edwin-zvs]

Summary:

• treat Done from an already non-running session as lifecycle teardown, not unseen activity
• preserve attention for silent work that finishes directly from Running and for errors
• add a persisted-marker regression test for an idle Pi session closing around daemon restart
• document the distinction in spec 0054

Verification:

• cargo test -p construct-daemon (720 passed)
• cargo build