app: wire checker retention janitor and user gate

Construct the retention janitor and the user gate alongside the
checker scheduler. Three new options drive their behaviour:

  --checker-retention-days        (default 365)
  --checker-janitor-interval      (default 6h)
  --checker-inactivity-pause-days (default 90)

The janitor starts immediately on App.Start and is shut down on
App.Stop. The user gate is installed on the scheduler with the same
storage-backed user resolver, so paused users and users that haven't
logged in for the configured horizon stop being checked until they
come back.

internal/app/app.go

@@ -76,6 +76,7 @@ type Usecases struct {
 	checkerPlanUC    *checkerUC.CheckPlanUsecase
 	checkerStatusUC  *checkerUC.CheckStatusUsecase
 	checkerScheduler *checkerUC.Scheduler
+	checkerJanitor   *checkerUC.Janitor
 }
 
 type App struct {
@@ -273,6 +274,21 @@ func (app *App) initUsecases() {
 	)
 	app.usecases.checkerScheduler = checkerUC.NewScheduler(app.usecases.checkerEngine, app.cfg.CheckerMaxConcurrency, app.store, app.store, app.store, app.store)
 
+	// Install the user-level gate so paused or long-inactive users do not
+	// get checked. The same user resolver is reused by the janitor for
+	// per-user retention overrides.
+	gater := checkerUC.NewUserGater(app.store, app.cfg.CheckerInactivityPauseDays)
+	app.usecases.checkerScheduler.SetGate(gater.Allow)
+
+	// Retention janitor.
+	app.usecases.checkerJanitor = checkerUC.NewJanitor(
+		app.store,
+		app.store,
+		app.store,
+		checkerUC.DefaultRetentionPolicy(app.cfg.CheckerRetentionDays),
+		app.cfg.CheckerJanitorInterval,
+	)
+
 	// Wire scheduler notifications for incremental queue updates.
 	domainService.SetSchedulerNotifier(app.usecases.checkerScheduler)
 	app.usecases.orchestrator.SetSchedulerNotifier(app.usecases.checkerScheduler)
@@ -348,6 +364,10 @@ func (app *App) Start() {
 		app.usecases.checkerScheduler.Start(context.Background())
 	}
 
+	if app.usecases.checkerJanitor != nil {
+		app.usecases.checkerJanitor.Start(context.Background())
+	}
+
 	log.Printf("Public interface listening on %s\n", app.cfg.Bind)
 	if err := app.srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
 		log.Fatalf("listen: %s\n", err)
@@ -365,6 +385,10 @@ func (app *App) Stop() {
 		app.usecases.checkerScheduler.Stop()
 	}
 
+	if app.usecases.checkerJanitor != nil {
+		app.usecases.checkerJanitor.Stop()
+	}
+
 	// Close storage
 	if app.store != nil {
 		app.store.Close()

internal/config/cli.go

@@ -25,6 +25,7 @@ import (
 	"flag"
 	"fmt"
 	"runtime"
+	"time"
 
 	"git.happydns.org/happyDomain/internal/storage"
 	"git.happydns.org/happyDomain/model"
@@ -47,6 +48,9 @@ func declareFlags(o *happydns.Options) {
 	flag.Var(&URL{&o.ExternalAuth}, "external-auth", "Base URL to use for login and registration (use embedded forms if left empty)")
 	flag.BoolVar(&o.OptOutInsights, "opt-out-insights", false, "Disable the anonymous usage statistics report. If you care about this project and don't participate in discussions, don't opt-out.")
 	flag.IntVar(&o.CheckerMaxConcurrency, "checker-max-concurrency", runtime.NumCPU(), "Maximum number of checker jobs that can run simultaneously")
+	flag.IntVar(&o.CheckerRetentionDays, "checker-retention-days", 365, "System-wide default retention horizon for check execution history (overridable per user)")
+	flag.DurationVar(&o.CheckerJanitorInterval, "checker-janitor-interval", 6*time.Hour, "How often the checker retention janitor runs")
+	flag.IntVar(&o.CheckerInactivityPauseDays, "checker-inactivity-pause-days", 90, "Pause checks for users that haven't logged in for this many days (0 disables, overridable per user)")
 
 	flag.Var(&URL{&o.ListmonkURL}, "newsletter-server-url", "Base URL of the listmonk newsletter server")
 	flag.IntVar(&o.ListmonkID, "newsletter-id", 1, "Listmonk identifier of the list receiving the new user")

model/config.go

@@ -26,6 +26,7 @@ import (
 	"net/mail"
 	"net/url"
 	"path"
+	"time"
 )
 
 // Options stores the configuration of the software.
@@ -97,6 +98,20 @@ type Options struct {
 	// run simultaneously. Defaults to runtime.NumCPU().
 	CheckerMaxConcurrency int
 
+	// CheckerRetentionDays is the system-wide default for how many days of
+	// check execution history are kept. Per-user UserQuota.RetentionDays
+	// overrides this value.
+	CheckerRetentionDays int
+
+	// CheckerJanitorInterval is how often the retention janitor runs.
+	CheckerJanitorInterval time.Duration
+
+	// CheckerInactivityPauseDays is the system-wide default number of days
+	// without login after which the scheduler stops running checks for a
+	// user. 0 disables inactivity pausing globally; per-user UserQuota
+	// overrides this value.
+	CheckerInactivityPauseDays int
+
 	// CaptchaProvider selects the captcha provider ("hcaptcha", "recaptchav2", "turnstile", or "").
 	CaptchaProvider string