Add settings-driven Artisan scheduler registry with Etsy sync and token refresh jobs

Introduces App\Support\DashboardSchedule (modelled on LHITS_Dashboard's
pattern) as a single settings-driven registry for recurring Artisan jobs,
replacing the two hard-coded Schedule::command() lines in
routes/console.php.

Migrated unchanged:
- integrations_refresh (integrations:refresh), every_30_seconds, withoutOverlapping(5)
- alerts_scan (alerts:scan), every_30_seconds, withoutOverlapping(5)

New:
- etsy_sync (etsy:sync), every_15_minutes - forces a fresh pull of Etsy
  receipts/listings into the existing IntegrationCache entries, decoupled
  from the bundled integrations:refresh job so it can be tuned/disabled
  independently of Parcel2Go/BamBuddy/dryer refreshes.
- etsy_token_refresh (etsy:refresh-token), every_45_minutes - proactively
  refreshes the Etsy OAuth token (tokens last ~1hr) via a new public
  Etsy::refreshAccessToken() wrapper around the existing on-demand
  accessToken() refresh logic, so the connection survives quiet periods.

Frequency is persisted to storage/app/dashboard-schedules.json (no
app_settings table exists in this app, unlike LHITS's AppSetting-backed
store) and surfaced in a new 'Scheduler' section on the existing Settings
page (ScheduleSettingsController + routes), with per-job frequency
dropdowns and manual 'Run now' buttons, matching the page's existing
Tailwind conventions.

Tests: SchedulerTest (registry/frequency behavior), ScheduleSettingsTest
(settings UI + authorization), EtsySyncScheduledJobsTest (new commands,
Http::fake only, no live Etsy calls).

routes/console.php

@@ -1,9 +1,8 @@
 <?php
 
+use App\Support\DashboardSchedule;
 use Illuminate\Foundation\DevCommands;
-use Illuminate\Support\Facades\Schedule;
 
-Schedule::command('integrations:refresh')->everyThirtySeconds()->withoutOverlapping(5);
-Schedule::command('alerts:scan')->everyThirtySeconds()->withoutOverlapping(5);
+DashboardSchedule::register();
 
 DevCommands::artisan('schedule:work', 'schedule');