feat(upload): add dynamic expiry options and modern UI theme

- Implement dynamic expiry options on the upload page based on user roles and retention policies.
- Add helper functions to build and format expiry options into human-readable labels.
- Introduce a new modern theme featuring glassmorphism, gradients, and frosted glass cards.

backend/libs/handlers/pages.go

@@ -9,11 +9,18 @@ import (
 )
 
 type homeData struct {
-	MaxUploadSize string
-	LimitSummary  string
-	Collections   []collectionView
-	IsAdmin       bool
-	AnonymousOpen bool
+	MaxUploadSize        string
+	LimitSummary         string
+	Collections          []collectionView
+	IsAdmin              bool
+	AnonymousOpen        bool
+	ExpiryOptions        []expiryOption
+	DefaultExpiryMinutes int
+}
+
+type expiryOption struct {
+	Minutes int
+	Label   string
 }
 
 func (a *App) Home(w http.ResponseWriter, r *http.Request) {
@@ -40,20 +47,92 @@ func (a *App) Home(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	maxUploadSize, limitSummary := a.homeUploadPolicyLabels(settings, user, loggedIn, isAdmin)
+	expiryOptions, defaultExpiry := a.homeExpiryOptions(settings, user, loggedIn, isAdmin)
 	a.renderPage(w, r, http.StatusOK, "home.html", web.PageData{
 		Title:       "Upload your files",
 		Description: "Upload and share files through a self-hosted Warpbox instance.",
 		CurrentUser: currentUser,
 		Data: homeData{
-			MaxUploadSize: maxUploadSize,
-			LimitSummary:  limitSummary,
-			Collections:   collections,
-			IsAdmin:       isAdmin,
-			AnonymousOpen: settings.AnonymousUploadsEnabled,
+			MaxUploadSize:        maxUploadSize,
+			LimitSummary:         limitSummary,
+			Collections:          collections,
+			IsAdmin:              isAdmin,
+			AnonymousOpen:        settings.AnonymousUploadsEnabled,
+			ExpiryOptions:        expiryOptions,
+			DefaultExpiryMinutes: defaultExpiry,
 		},
 	})
 }
 
+// homeExpiryOptions builds the expiry ladder offered on the upload form, capped to
+// the viewer's effective maximum retention. Admins have no cap (the dropdown is
+// still capped at 365 days for sanity; the API accepts any value for admins).
+func (a *App) homeExpiryOptions(settings services.UploadPolicySettings, user services.User, loggedIn, isAdmin bool) ([]expiryOption, int) {
+	maxDays := settings.AnonymousMaxDays
+	unlimited := false
+	switch {
+	case isAdmin:
+		unlimited = true
+	case loggedIn:
+		maxDays = a.settingsService.EffectivePolicyForUser(settings, user).MaxDays
+	}
+	return buildExpiryOptions(maxDays, unlimited)
+}
+
+func buildExpiryOptions(maxDays int, unlimited bool) ([]expiryOption, int) {
+	ladder := []int{60, 720, 1440, 2880, 4320, 7200, 10080, 14400, 20160, 43200, 86400, 129600, 259200, 525600}
+
+	capMinutes := maxDays * 24 * 60
+	if unlimited || capMinutes <= 0 {
+		capMinutes = 525600
+	}
+
+	options := make([]expiryOption, 0, len(ladder)+1)
+	seen := make(map[int]bool)
+	for _, minutes := range ladder {
+		if minutes > capMinutes {
+			break
+		}
+		options = append(options, expiryOption{Minutes: minutes, Label: expiryLabel(minutes)})
+		seen[minutes] = true
+	}
+	// Always offer the exact cap as a final choice (e.g. a 15-day limit).
+	if !unlimited && !seen[capMinutes] {
+		options = append(options, expiryOption{Minutes: capMinutes, Label: expiryLabel(capMinutes)})
+	}
+	if len(options) == 0 {
+		options = append(options, expiryOption{Minutes: capMinutes, Label: expiryLabel(capMinutes)})
+	}
+
+	// Default to 24h when available, otherwise the smallest option offered.
+	defaultMinutes := options[0].Minutes
+	if seen[1440] {
+		defaultMinutes = 1440
+	}
+	return options, defaultMinutes
+}
+
+func expiryLabel(minutes int) string {
+	switch {
+	case minutes < 60:
+		return strconv.Itoa(minutes) + " minutes"
+	case minutes < 1440:
+		hours := minutes / 60
+		if hours == 1 {
+			return "1 hour"
+		}
+		return strconv.Itoa(hours) + " hours"
+	case minutes == 1440:
+		return "24 hours"
+	default:
+		days := minutes / 1440
+		if days == 1 {
+			return "1 day"
+		}
+		return strconv.Itoa(days) + " days"
+	}
+}
+
 func (a *App) homeUploadPolicyLabels(settings services.UploadPolicySettings, user services.User, loggedIn, isAdmin bool) (string, string) {
 	if isAdmin {
 		return "No file size limit", "Admin uploads bypass storage and daily caps."