Scope washer/dryer cycle translations to the device's own course table

Course codes on the shared /course/vs/0 contract aren't guaranteed
consistent across board generations: washer/combo devices report course
table Table_02, dryer devices Table_03 (x.com.samsung.da.st.courseTable,
previously fully ignored), and every code in washer_cycle/dryer_cycle was
confirmed exclusively against those. FlexWash's older DA_WM_A51 board
reports Table_00 instead -- applying the same translations there risked
showing a wrong name for any code that happens to numerically collide
between tables, not just an untranslated one.

SelectDesc.translation_key can now be a callable (resources -> key or
None), mirroring the existing pattern for `options`. laundry.cycle_select
gains optional table_href/validated_table params: when given, the renamed
washer_cycle_table_02/dryer_cycle_table_03 keys only apply when the
device's own course table matches exactly -- a different table, or no
table id at all, gets no translation_key (raw code display) rather than
a guess. dishwasher's call site is unchanged (static key, unconditional):
no equivalent table-id resource exists in any dump seen, and no evidence
its course codes vary by table the way washer/dryer's do.

entity.py and select.py resolve a callable translation_key once (via
coordinator.last_resources) and reuse that resolved value everywhere
_display() needs it, rather than re-checking the raw descriptor field.

tests/test_select_display.py

@@ -1,9 +1,8 @@
 """Tests for select-option display casing (custom_components/localthings/select.py)."""
-from custom_components.localthings.registry.entities import SelectDesc
 from custom_components.localthings.select import _display
 
-_UNTRANSLATED = SelectDesc(key='x', options=())
-_TRANSLATED = SelectDesc(key='y', options=(), translation_key='door_alert')
+_UNTRANSLATED = None
+_TRANSLATED = 'door_alert'
 
 
 def test_display_titlecases_a_fully_lowercase_device_native_token():