fix(climate): derive presets only when the board publishes both capability maps

One map is not enough to judge by: with only OptionCode present, every
eoc-gated rule reads None, and None means the board does not publish the map
rather than that the feature is absent. artik051_dongle_fac_18k is exactly that
board and lost WindFree in every mode. Requiring both also keeps these bit
positions inside the family they were documented for -- the FAC and CAC dumps
carry only the older map, with values small enough that RAC positions read as
zeros.

Also from review: an unknown HVAC mode falls back the same way, Comfort is
spelled like the identical Speed rule, the unreachable AIComfort branch is
gone, the Cool code comes from the unit's own supportedModes, DlightCool gains
its catalog entry, and the Single User claim is dropped -- the app's own Single
User command sends Comode_Smart, so there is no distinct token to write.

tests/test_airconditioner_artik051_krac.py

@@ -529,11 +529,73 @@ def test_presets_follow_the_hvac_mode_and_the_capability_bits():
         assert _in_mode(mode) == ["none", "nano"]
     # Auto: WindFree only because this is an 18K model.
     assert _in_mode("Auto") == ["none", "nano"]
-    # Nothing offers what the bits deny, in any mode.
+    # d'light Cool is a live rule and this unit's oc[2] denies it everywhere.
     for mode in ("Cool", "Heat", "Dry", "Wind", "Auto"):
-        presets = _in_mode(mode)
-        assert "dlightcool" not in presets, mode
-        assert "singleuser" not in presets, mode
+        assert "dlightcool" not in _in_mode(mode), mode
+
+
+def test_a_board_with_only_the_old_map_keeps_the_unconditional_list():
+    """One map is not enough to judge by. `airconditioner_artik051_dongle_fac_18k`
+    is a legacy board that publishes OptionCode and no ExtendOptionCode, so every
+    eoc-gated rule would read None -- and None means "this board does not publish
+    the map", not "the feature is absent". Deriving from it would have cost that
+    unit WindFree in every mode, and left it with ['none'] alone in its own
+    fixture mode.
+
+    Its OptionCode is also 521, three orders of magnitude below the RAC-class
+    values these bit positions were read from, which is the second reason not to
+    interpret it: the FAC and CAC families use the field differently.
+    """
+    resources = _load_device("airconditioner_artik051_dongle_fac_18k")
+    options = resources["/mode/vs/0"]["x.com.samsung.da.options"]
+    assert any(o.startswith("OptionCode_") for o in options)
+    assert not any(o.startswith("ExtendOptionCode_") for o in options)
+
+    baseline = ["none", "nano", "quiet", "comfort", "2step", "speed"]
+    for mode in ("Auto", "Cool", "Heat", "Dry", "Wind"):
+        resources["/mode/vs/0"]["x.com.samsung.da.modes"] = [mode]
+        assert _climate(resources).preset_modes == baseline, mode
+
+
+def test_the_other_board_with_both_maps_still_derives():
+    """`airconditioner_artik051_krac_energy` is the same model as the fixture
+    above with a different OptionCode (56378), and carries both maps -- so it
+    stays on the derived path rather than the fallback."""
+    presets = _in_mode("Cool", fixture="airconditioner_artik051_krac_energy")
+    assert presets[:1] == ["none"]
+    assert "nano" in presets and "smart" in presets
+    assert presets != ["none", "nano", "quiet", "comfort", "2step", "speed"]
+
+
+def test_an_unknown_hvac_mode_falls_back_instead_of_deriving():
+    """An HVAC mode these rules have never seen is the same "cannot judge" case
+    as an absent map, so it gets the same answer rather than a derived-but-wrong
+    one. Reachable with a partial or malformed rep, where `modes` is missing."""
+    resources = _load_device(FIXTURE)
+    for modes in ([], ["CoolClean"]):
+        resources["/mode/vs/0"]["x.com.samsung.da.modes"] = modes
+        assert _climate(resources).preset_modes == [
+            "none",
+            "nano",
+            "quiet",
+            "comfort",
+            "2step",
+            "speed",
+        ], modes
+
+
+async def test_aicomfort_neither_offers_nano_nor_switches_the_mode():
+    """The app disables WindFree in AIComfort, so it is not offered -- and the
+    Cool-first write is therefore Auto-only, with no unreachable branch for a
+    mode that can never ask for it."""
+    resources = _load_device(FIXTURE)
+    resources["/mode/vs/0"]["x.com.samsung.da.modes"] = ["AIComfort"]
+    coordinator = _FakeCoordinator(resources)
+    entity = _climate(resources, coordinator)
+
+    assert "nano" not in entity.preset_modes
+    await entity.async_set_preset_mode("quiet")
+    assert [payload for _, payload in coordinator.commands] == [("preset_legacy", "Quiet")]
 
 
 def test_a_bit_that_is_zero_removes_its_preset():