[client] UI refactor (#6069)

Refactor UI

---------

Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: braginini <bangvalo@gmail.com>
Co-authored-by: Pascal Fischer <32096965+pascal-fischer@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: riccardom <riccardomanfrin@gmail.com>

client/internal/auth/sessionwatch/event.go

@@ -0,0 +1,82 @@
+package sessionwatch
+
+import (
+	"strconv"
+	"time"
+)
+
+// internal event kinds are no longer exposed: the watcher drives the Sink
+// directly (NotifyStateChange on deadline change/clear, PublishEvent at
+// each warning lead). Tests use a mock Sink to observe what the watcher
+// emits.
+
+// Metadata keys attached by the daemon to session-warning SystemEvents.
+// The UI tray reads these to build a locale-aware notification without
+// relying on the daemon's locale-less UserMessage string, and to
+// disambiguate the T-WarningLead notification from the T-FinalWarningLead
+// fallback that auto-opens the SessionAboutToExpire dialog.
+const (
+	// MetaSessionWarning is set to "true" on both warning events (T-10 and
+	// T-2) so the UI can detect a session-warning SystemEvent without
+	// matching on the message text. Use MetaSessionFinal to distinguish
+	// the two.
+	MetaSessionWarning = "session_warning"
+	// MetaSessionFinal is set to "true" on the T-FinalWarningLead event
+	// only. Consumers that need to auto-open the SessionAboutToExpire
+	// dialog gate on this; T-WarningLead events leave the field unset.
+	MetaSessionFinal = "session_final_warning"
+	// MetaSessionExpiresAt carries the absolute UTC deadline encoded with
+	// FormatExpiresAt; consumers must decode with ParseExpiresAt so a
+	// future format change stays a single edit.
+	MetaSessionExpiresAt = "session_expires_at"
+	// MetaSessionLeadMinutes carries the lead in whole minutes (WarningLead
+	// for the T-10 event, FinalWarningLead for the T-2 event) so the UI
+	// can show "expires in ~N minutes" without hardcoding either constant.
+	MetaSessionLeadMinutes = "lead_minutes"
+	// MetaSessionDeadlineRejected is attached to the ERROR/AUTHENTICATION
+	// SystemEvent the daemon emits when it discards a deadline from the
+	// management server (pre-epoch, too far in the future, or past the
+	// clock-skew tolerance). The value is the rejection reason string.
+	// userMessage is left empty; the UI detects the event via this key
+	// and builds a localized notification — same pattern as the session
+	// warnings above.
+	MetaSessionDeadlineRejected = "session_deadline_rejected"
+)
+
+// expiresAtLayout is the wire format used for MetaSessionExpiresAt.
+// Producer and consumers both go through FormatExpiresAt/ParseExpiresAt
+// so this layout stays a single source of truth.
+const expiresAtLayout = time.RFC3339
+
+// FormatExpiresAt encodes a deadline for MetaSessionExpiresAt. Always
+// emits UTC so a consumer in another timezone reads the same wall-clock
+// deadline.
+func FormatExpiresAt(t time.Time) string {
+	return t.UTC().Format(expiresAtLayout)
+}
+
+// ParseExpiresAt decodes the MetaSessionExpiresAt value back to a UTC
+// time. Returns an error when the field is empty or malformed; the
+// caller decides whether to fall back (zero value) or propagate.
+func ParseExpiresAt(s string) (time.Time, error) {
+	t, err := time.Parse(expiresAtLayout, s)
+	if err != nil {
+		return time.Time{}, err
+	}
+	return t.UTC(), nil
+}
+
+// FormatLeadMinutes encodes a lead duration for MetaSessionLeadMinutes
+// as the integer count of whole minutes. Sub-minute residuals are
+// truncated — the field is informational ("expires in ~N minutes") and
+// fractional minutes don't change what the UI displays.
+func FormatLeadMinutes(d time.Duration) string {
+	return strconv.Itoa(int(d / time.Minute))
+}
+
+// ParseLeadMinutes decodes a MetaSessionLeadMinutes value. Returns 0
+// and the parse error for malformed input; consumers that prefer a
+// silent fallback can simply ignore the error.
+func ParseLeadMinutes(s string) (int, error) {
+	return strconv.Atoi(s)
+}