Coordinator polls the API snapshot and rebuilds the sensors' data

Feature 18: the shared coordinator's refresh pass now fetches
GET /api/v1/panel/snapshot through the NestQuestApiClient and
reconstructs the exact core dataclasses (NestQuestSnapshot,
ChildDaySnapshot, QuestInstanceView) the Feature 10 entities read, so
sensor.py and binary_sensor.py are untouched and every entity_id and
attribute payload keeps its shape.

Why: the integration becomes an API client of the NestQuest service
instead of a second reader of the SQLite file, and the panel cards and
the four blueprints keep working without changes.

- snapshot_from_api_payload maps the route's JSON back onto the
  dataclasses field by field (state 'completed' -> 'done' so
  instance_payload renders 'completed' again; counts, presence,
  next_present, overdue, on_time, completed_at pass through verbatim;
  due_date is stamped from today_iso, the only date the route serves).
- The panel payload omits missed instances (D-009), so
  admin_instances can no longer carry missed rows — the admin surface
  for missed quests is the PWA reading the API directly. Documented in
  the module docstring and pinned by tests.
- An unconfigured panel token (the shipped default) gets a typed-error
  stub instead of a construction crash: setup succeeds, the first
  refresh fails cleanly, entities come up unavailable and HA's retry
  cycle applies. Fetch failures log the typed error and mark the
  entities unavailable while data keeps its last good snapshot.
- The runtime record registers before the first refresh so the refresh
  path always finds the live entry state; the update interval and the
  serialized forced-refresh behaviour are unchanged.
- Tests: a fixture snapshot drives the coordinator (stub client, no
  network) asserting per-child values, household rollups, cycle day,
  and the exact instance payload shape, plus unconfigured and
  failed-fetch cases; DB-seeded tests ride a lazy local-snapshot
  client through the same JSON path.

custom_components/nestquest/__init__.py

@@ -16,6 +16,7 @@ from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import ConfigEntryNotReady
 from homeassistant.helpers.event import async_track_time_change
 
+from .api_client import NestQuestApiError
 from .const import (
     CONF_ADMIN_USER_IDS,
     CONF_UPDATE_INTERVAL,
@@ -26,7 +27,7 @@ from .const import (
 )
 from .core.settings import NestQuestSettings
 from .frontend import async_register_frontend
-from .coordinator import NestQuestCoordinator
+from .coordinator import NestQuestCoordinator, coordinator_client_from_entry
 from .db import NestQuestDatabase, make_database
 from .materialize import materialize as _materialize_run
 from .migrations import apply_migrations
@@ -490,18 +491,20 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         _register_services(hass)
         # The shared Feature 10 coordinator: one refresh cycle every
         # entity reads from (CONF_UPDATE_INTERVAL seconds, default
-        # five minutes).  Created AFTER services so a failure below
-        # unwinds them through the except path's listener handling.
+        # five minutes).  Since Feature 18 it polls the API service's
+        # panel snapshot instead of reading the local database; an
+        # entry with no panel token yet gets the typed-error stub
+        # (unavailable entities, never a setup crash).  Created AFTER
+        # services so a failure below unwinds them through the except
+        # path's listener handling.
         coordinator = NestQuestCoordinator(
             hass,
             entry_id=entry.entry_id,
-            database=database,
-            settings=settings,
+            api_client=coordinator_client_from_entry(hass, entry),
             update_interval_seconds=entry.options.get(
                 CONF_UPDATE_INTERVAL, DEFAULT_UPDATE_INTERVAL
             ),
         )
-        await coordinator.async_config_entry_first_refresh()
         runtime_data = NestQuestRuntimeData(
             entry_id=entry.entry_id,
             settings=settings,
@@ -510,11 +513,24 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
             remove_time_change_listener=remove_time_change_listener,
             coordinator=coordinator,
         )
-        # runtime_data is assigned BEFORE the platforms forward so each
-        # platform's async_setup_entry reads its coordinator off the
-        # entry (the HA runtime-data contract); a forward failure below
+        # The runtime record is registered BEFORE the first refresh:
+        # the refresh path (and anything it calls) resolves the entry's
+        # runtime state through hass.data, and it must find the live
+        # database there — never a half-set-up entry.  The platforms
+        # forward below reads the coordinator off the entry
+        # (the HA runtime-data contract); a forward failure below
         # unwinds it through the except path.
+        hass.data[DOMAIN][entry.entry_id] = runtime_data
         entry.runtime_data = runtime_data
+        # The first refresh polls the API snapshot; an API failure
+        # (unconfigured token, API service down) does NOT crash setup:
+        # the coordinator reports last_update_success=False, entities
+        # come up unavailable, and HA's standard retry cycle applies
+        # once the API is reachable.  Any non-API error still raises.
+        try:
+            await coordinator.async_config_entry_first_refresh()
+        except NestQuestApiError:
+            pass
         await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
     except BaseException:
         # A failure anywhere after the database is open must not leak the
@@ -552,6 +568,9 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         raise
     assert remove_update_listener is not None
     assert remove_time_change_listener is not None
+    # The runtime record was already registered before the first
+    # refresh; re-assert the (unchanged) record so the return path
+    # stays readable as one registration site.
     hass.data[DOMAIN][entry.entry_id] = runtime_data
     return True