feat(reminders): Phase 4 partial — schema + service + validators

Migration 0072 — reminders/interests expansion:
- interests.reminder_note: optional cadence note for the existing
  reminderEnabled+reminderDays flow. Surfaces in notification body
  + inbox row.
- reminders.yacht_id (+ FK + relation): fourth entity link so
  yacht-scoped tasks have a typed home alongside client/interest/berth.
- reminders.fired_at: worker idempotency. Partial index
  idx_reminders_due_unfired drives the scan.

Service + validator updates:
- createReminderSchema / updateReminderSchema accept yachtId.
- assertReminderFksInPort validates yacht ownership against the
  caller's port — defense-in-depth, same shape as other entity FKs.
- createReminder / updateReminder thread yachtId through.

Worker scheduler + CreateReminderDialog yachtId UI deferred. The
existing reminders/reminder-form.tsx already covers the dialog
contract — Phase 4b extends it with yachtId + the per-user
digest_time_of_day picker.

Tests: 1374/1374 passing. tsc clean.

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

src/lib/db/schema/interests.ts

@@ -74,6 +74,9 @@ export const interests = pgTable(
     reminderEnabled: boolean('reminder_enabled').notNull().default(false),
     reminderDays: integer('reminder_days'),
     reminderLastFired: timestamp('reminder_last_fired', { withTimezone: true }),
+    // Phase 4: optional note surfaced in the reminder notification body
+    // and inbox row. NULL = use the default cadence copy.
+    reminderNote: text('reminder_note'),
     /** Terminal outcome. Independent of pipelineStage - `outcome` is set
      *  alongside the stage transition to `completed` to distinguish won
      *  deals from the various lost variants. NULL while the interest is