The integration no longer owns a database

The HA integration is now purely a client of the NestQuest API service
(Feature 18): the API owns the SQLite file, the migrations, and every
business rule, so keeping a second copy of that ownership inside the
integration meant two sources of truth for household state, dead
wiring (the startup backfill, the day-rollover materialization and
sweep listeners, the corrupt-DB handling, the admin-allowlist seeding)
and settings keys nothing consumes any more.

Removed the integration's re-export/DB shim modules (db, store,
migrations, schema, the five DAOs, completion, children,
quest_definitions, admin_allowlist, presence, presence_management,
materialize, recurrence, events, sweep); the bundled domain package at
custom_components/nestquest/core/ is untouched and remains the single
home of those engines.  Setup now builds only the API client, the
snapshot coordinator, and the SSE subscription, registers the one
complete_quest proxy, and forwards the platforms.  The options flow
keeps only the keys the client itself consumes (API base URL + panel
token, update interval, staleness, panel idle timeout); the horizon,
rollover, notification and admin-allowlist settings moved out with the
database (the API's settings store owns horizon/rollover, and the
automations take their behaviour from blueprint inputs).  The
integration-plane tests now script the panel route's payloads and SSE
frames instead of seeding a local database; the core-plane tests keep
their coverage with imports pointed at core directly.

custom_components/nestquest/strings.json

@@ -18,25 +18,19 @@
     "step": {
       "init": {
         "title": "NestQuest Settings",
-        "description": "Adjust how NestQuest plans, rolls over days, idles its panel, and reaches the NestQuest API service.",
+        "description": "Adjust how the NestQuest API client polls and reaches the NestQuest API service.",
         "data": {
-          "horizon_days": "Generation horizon (days)",
-          "day_rollover_time": "Day rollover time (HH:MM)",
           "panel_idle_timeout": "Panel idle timeout (seconds)",
           "snapshot_staleness": "Last-good snapshot staleness (seconds)",
           "api_base_url": "NestQuest API base URL (http://host:port)",
-          "panel_token": "Panel service token",
-          "admin_user_ids": "Admin users (parents)"
+          "panel_token": "Panel service token"
         }
       }
     },
     "errors": {
       "invalid": "Invalid value.",
-      "invalid_time": "Time must use 24-hour HH:MM format.",
       "invalid_url": "Enter the API base URL as a full http:// or https:// URL with a host.",
-      "invalid_staleness": "Last-good snapshot staleness must be at least the update interval.",
-      "no_admins": "Select at least one admin user; an empty allowlist would lock everyone out.",
-      "invalid_admin": "Invalid admin selection."
+      "invalid_staleness": "Last-good snapshot staleness must be at least the update interval."
     }
   }
 }