laundry: a post-Finish running stage is the cycle ending, not a new one

Fixes #358, a regression from #346. That PR's sticky_bypass_fn released
the Finish/100 hold on any concrete non-Finish progress code, ungated on
machine_state, reasoning that a new cycle's own progress can appear
before state catches up. But the reporting DA_WM_TP1_21_COMMON dryer
replays a running stage on the way *out* of a cycle: the issue's history
shows Cooling -> +60s Finish -> +24s 'Drying' -> +4s settled, twice,
identically. The bypass read that tail as a new cycle, dropped the hold,
and republished 'Drying' -- so progress read Drying, Cooling, Finish,
Drying, Idle instead of ending at Finish, Idle.

The tail is not new: rep_fn has always masked progress while state isn't
active, which is why it was invisible before #346. What surfaced it was
sticky_live_fn, a second, ungated view of the same field that the bypass
returned in rep_fn's place -- letting the hold publish a value the entity
otherwise never shows.

Both halves are fixed:

- The bypass (now _new_cycle_running) requires state == 'active'
  alongside the progress code. The arm condition stays ungated -- failing
  to arm loses the Finish entirely (#345), while releasing late costs
  nothing, since the hold expires on its own.
- sticky_live_fn is gone. rep_fn is the only definition of a live value;
  the hold decides only whether to freeze, and the bypass returns rep_fn's
  own result.

Also stop an already-open window from being restarted by a progress that
flaps in and out of Finish, so sticky_seconds is measured from the first
Finish of a cycle and the documented bound actually holds.

A paused new cycle no longer cuts the hold short (it did under the old
ungated bypass). Nothing live is withheld by that: rep_fn shows Idle
while paused with or without a hold, so the only change is a stale Finish
expiring on schedule -- and 'paused' cannot be told apart from this tail.

tests/test_sensor_sticky.py

@@ -165,22 +165,100 @@ def test_a_new_cycle_starting_overrides_the_hold():
     assert sensor.native_value == "Wash"
 
 
-def test_a_paused_new_cycle_also_overrides_the_hold():
-    """Not just an actively-running new cycle: adding a sock and pausing
-    mid-cycle must also show the real, current progress rather than a
-    stale hold from the previous cycle -- machine_state isn't 'active'
-    while paused, so a bypass keyed on that alone would miss this."""
-    sensor, coordinator = _sensor(_PROGRESS_DESC)
+def test_a_running_stage_after_finish_does_not_break_the_hold():
+    """Issue #358: the reporting dryer replays a running stage after
+    Finish -- observed twice, identically, as Cooling -> +60s Finish ->
+    +24s 'Drying' -> +4s settled, with `state` already idle throughout the
+    tail. The hold must survive it, so the cycle still reads Drying,
+    Cooling, Finish, Idle rather than the reported Drying, Cooling,
+    Finish, Drying, Idle."""
+    desc = replace(_PROGRESS_DESC, sticky_seconds=0.2)
+    sensor, coordinator = _sensor(desc)
+
+    _replace(coordinator, state="Run", progress="Drying", progressPercentage="40")
+    assert sensor.native_value == "Drying"
+
+    _replace(coordinator, state="Run", progress="Cooling", progressPercentage="95")
+    assert sensor.native_value == "Cooling"
+
+    _replace(coordinator, state="Run", progress="Finish", progressPercentage="100")
+    assert sensor.native_value == "Finish"
+
+    # The tail: a running stage again, state already idle.
+    _replace(coordinator, state="Ready", progress="Drying", progressPercentage="100")
+    assert sensor.native_value == "Finish"
+
+    # ...then the device settles, still inside the window.
+    _replace(coordinator, state="Ready", progress="None")
+    assert sensor.native_value == "Finish"
+
+    time.sleep(0.25)
+    assert sensor.native_value == "Idle"
+
+
+def test_progress_percentage_survives_the_same_tail():
+    """#358's tail hits progress_percentage through the identical bypass;
+    it must stay pinned at 100 rather than being released back to a raw
+    mid-cycle figure."""
+    desc = replace(_PROGRESS_PERCENTAGE_DESC, sticky_seconds=0.2)
+    sensor, coordinator = _sensor(desc)
+
+    _replace(coordinator, state="Run", progress="Finish", progressPercentage="100")
+    assert sensor.native_value == 100
+
+    _replace(coordinator, state="Ready", progress="Drying", progressPercentage="40")
+    assert sensor.native_value == 100
+
+    time.sleep(0.25)
+    assert sensor.native_value == 0
+
+
+def test_a_paused_new_cycle_is_left_to_the_window_rather_than_released():
+    """'Paused' isn't positive evidence of a new cycle, and #358's tail is
+    indistinguishable from it. Nothing live is withheld by waiting --
+    rep_fn shows 'Idle' while paused with or without a hold -- so the
+    stale Finish just expires on schedule instead of being cut short."""
+    desc = replace(_PROGRESS_DESC, sticky_seconds=0.05)
+    sensor, coordinator = _sensor(desc)
 
     _replace(coordinator, state="Run", progress="Finish", progressPercentage="100")
     assert sensor.native_value == "Finish"
-    _replace(coordinator, state="Ready")
-    assert sensor.native_value == "Finish"  # still held
 
     _replace(coordinator, state="Pause", progress="Wash")
+    assert sensor.native_value == "Finish"  # held out, not released
+
+    time.sleep(0.1)
+    assert sensor.native_value == "Idle"  # what a paused appliance always shows
+
+    _replace(coordinator, state="Run", progress="Wash")
     assert sensor.native_value == "Wash"
 
 
+def test_a_flapping_finish_cannot_ratchet_the_window_forward():
+    """Edge-triggering stops a *stuck* Finish from extending the hold, but
+    a device whose progress flaps out of and back into Finish re-arms --
+    an already-open window must not restart on that, or the bound stops
+    being a bound."""
+    desc = replace(_PROGRESS_DESC, sticky_seconds=0.1)
+    sensor, coordinator = _sensor(desc)
+
+    _replace(coordinator, state="Ready", progress="Finish")
+    assert sensor.native_value == "Finish"
+
+    for _ in range(3):
+        time.sleep(0.03)
+        _replace(coordinator, state="Ready", progress="None")
+        assert sensor.native_value == "Finish"
+        _replace(coordinator, state="Ready", progress="Finish")
+        assert sensor.native_value == "Finish"
+
+    # 0.09s of flapping so far; past 0.1s from the *first* Finish it ends,
+    # rather than 0.1s from the most recent re-arm.
+    time.sleep(0.03)
+    _replace(coordinator, state="Ready", progress="Finish")
+    assert sensor.native_value == "Idle"
+
+
 def test_hold_expires_after_sticky_seconds():
     # A fresh desc (frozen dataclass -- replace(), not mutation, so the
     # module-level _PROGRESS_DESC other tests share stays untouched) with