feat(maintenance): schema for reminders dedup log

Phase 1 of the maintenance-reminders feature.

- notification_kind: + maintenance_due_soon, maintenance_overdue.
  These are distinct from maintenance_event_recorded (service
  performed) so the bell list can group/filter reminder vs service
  cleanly.
- New maintenance_reminder_kind enum: due_soon | overdue.
- New maintenance_reminders_sent table with UNIQUE(schedule_id,
  kind, due_at). The cron uses INSERT … ON CONFLICT DO NOTHING on
  this composite to make the fire-once-per-window guarantee atomic
  even under concurrent runs. Once the schedule's next_due_at
  advances after a service event, the tuple is fresh and a new
  reminder fires.

No service code yet — Phase 2 wires the readers and orchestrator.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

drizzle/0019_maintenance_reminders.sql

@@ -0,0 +1,14 @@
+CREATE TYPE "public"."maintenance_reminder_kind" AS ENUM('due_soon', 'overdue');--> statement-breakpoint
+ALTER TYPE "public"."notification_kind" ADD VALUE 'maintenance_due_soon' BEFORE 'generic';--> statement-breakpoint
+ALTER TYPE "public"."notification_kind" ADD VALUE 'maintenance_overdue' BEFORE 'generic';--> statement-breakpoint
+CREATE TABLE "maintenance_reminders_sent" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"schedule_id" uuid NOT NULL,
+	"kind" "maintenance_reminder_kind" NOT NULL,
+	"due_at" timestamp with time zone NOT NULL,
+	"fired_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+ALTER TABLE "maintenance_reminders_sent" ADD CONSTRAINT "maintenance_reminders_sent_schedule_id_maintenance_schedules_id_fk" FOREIGN KEY ("schedule_id") REFERENCES "public"."maintenance_schedules"("id") ON DELETE cascade ON UPDATE no action;--> statement-breakpoint
+CREATE UNIQUE INDEX "mrs_schedule_kind_due_uq" ON "maintenance_reminders_sent" USING btree ("schedule_id","kind","due_at");--> statement-breakpoint
+CREATE INDEX "mrs_by_schedule" ON "maintenance_reminders_sent" USING btree ("schedule_id","kind");

drizzle/meta/_journal.json

@@ -134,6 +134,13 @@
       "when": 1777268985448,
       "tag": "0018_checklist_scope_property",
       "breakpoints": true
+    },
+    {
+      "idx": 19,
+      "version": "7",
+      "when": 1777281036233,
+      "tag": "0019_maintenance_reminders",
+      "breakpoints": true
     }
   ]
 }

src/lib/server/db/schema/_shared.ts

@@ -76,8 +76,15 @@ export const notificationKindEnum = pgEnum('notification_kind', [
 	'asset_moved',
 	'decision_created',
 	'maintenance_event_recorded',
+	'maintenance_due_soon',
+	'maintenance_overdue',
 	'generic'
 ]);
+
+export const maintenanceReminderKindEnum = pgEnum('maintenance_reminder_kind', [
+	'due_soon',
+	'overdue'
+]);
 export const expenseKindEnum = pgEnum('expense_kind', [
 	'water',
 	'electricity',

src/lib/server/db/schema/maintenance.ts

@@ -1,8 +1,16 @@
-import { pgTable, varchar, text, integer, numeric, timestamp, boolean, index } from 'drizzle-orm/pg-core';
+import { pgTable, varchar, text, integer, numeric, timestamp, boolean, index, uniqueIndex } from 'drizzle-orm/pg-core';
 import { users } from './tenancy';
 import { assets } from './assets';
 import { checklistTemplates, checklistInstances } from './checklists';
-import { scheduleKindEnum, intervalUnitEnum, pk, fk, createdAt, updatedAt } from './_shared';
+import {
+	scheduleKindEnum,
+	intervalUnitEnum,
+	maintenanceReminderKindEnum,
+	pk,
+	fk,
+	createdAt,
+	updatedAt
+} from './_shared';
 
 export const maintenanceSchedules = pgTable(
 	'maintenance_schedules',
@@ -80,7 +88,32 @@ export const maintenanceEvents = pgTable(
 	})
 );
 
+// Dedup log for the reminder cron. We insert (schedule_id, kind, due_at)
+// before firing notify(); the unique index makes the insert atomic, so
+// concurrent or repeated runs cannot double-fire for the same window.
+// After service is recorded, schedules.next_due_at advances → new tuple →
+// reminder fires fresh. Rows are kept indefinitely for audit; a separate
+// cleanup task can prune > 90 days old.
+export const maintenanceRemindersSent = pgTable(
+	'maintenance_reminders_sent',
+	{
+		id: pk(),
+		scheduleId: fk('schedule_id')
+			.notNull()
+			.references(() => maintenanceSchedules.id, { onDelete: 'cascade' }),
+		kind: maintenanceReminderKindEnum('kind').notNull(),
+		dueAt: timestamp('due_at', { withTimezone: true }).notNull(),
+		firedAt: timestamp('fired_at', { withTimezone: true }).notNull().defaultNow()
+	},
+	(t) => ({
+		// The dedup key. INSERT … ON CONFLICT DO NOTHING relies on this.
+		dedupUq: uniqueIndex('mrs_schedule_kind_due_uq').on(t.scheduleId, t.kind, t.dueAt),
+		bySchedule: index('mrs_by_schedule').on(t.scheduleId, t.kind)
+	})
+);
+
 export type MaintenanceSchedule = typeof maintenanceSchedules.$inferSelect;
 export type NewMaintenanceSchedule = typeof maintenanceSchedules.$inferInsert;
 export type UsageReading = typeof usageReadings.$inferSelect;
 export type MaintenanceEvent = typeof maintenanceEvents.$inferSelect;
+export type MaintenanceReminderSent = typeof maintenanceRemindersSent.$inferSelect;