Make delivery and integration failures explicit

Persist reminder presentations and retry state, atomically complete collapsed deliveries, fall back across away reaches, and block permanent failures visibly (V-715, V-678). Fail closed when enabled integrations lack credentials and keep remote arms explicitly dark (V-691). Give mavweb one sanitized, request-correlated error contract (V-689). Owner explicitly requested direct commits to master.

cmd/mavweb/reminders.go

@@ -3,7 +3,7 @@ package main
 import (
 	_ "embed"
 	"encoding/json"
-	"log"
+	"fmt"
 	"net/http"
 	"strings"
 
@@ -26,6 +26,7 @@ type reminderRow struct {
 	Created string
 	Fires   string
 	Status  string
+	Detail  string
 	Text    string
 }
 
@@ -50,10 +51,19 @@ func reminderText(payload string) string {
 func reminderRows(rs []ipc.Reminder) []reminderRow {
 	out := make([]reminderRow, 0, len(rs))
 	for _, r := range rs {
+		status := r.Status
+		detail := ""
+		if !r.DeliveryBlockedTs.IsZero() {
+			status = "blocked"
+			detail = r.DeliveryBlockedError
+		} else if r.DeliveryAttempts > 0 && !r.NextAttemptTs.IsZero() {
+			detail = "retry " + r.NextAttemptTs.Local().Format("02 Jan 15:04")
+		}
 		out = append(out, reminderRow{
 			Created: r.CreatedTs.Local().Format("02 Jan 15:04"),
 			Fires:   r.FireTs.Local().Format("02 Jan 15:04"),
-			Status:  r.Status,
+			Status:  status,
+			Detail:  detail,
 			Text:    reminderText(r.Payload),
 		})
 	}
@@ -61,13 +71,13 @@ func reminderRows(rs []ipc.Reminder) []reminderRow {
 }
 
 func handleReminders(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI) {
-	if !requireCore(w, core, "reminders") {
+	if !requireCore(w, r, core, "reminders") {
 		return
 	}
 	reminders, err := core.ListReminders(r.Context(), 50)
 	if err != nil {
-		log.Printf("reminders: %v", err)
-		http.Error(w, "reminders error: "+err.Error(), http.StatusBadGateway)
+		writeProblem(w, r, http.StatusBadGateway, problemCoreReadFailed,
+			"reminders unavailable", fmt.Errorf("list reminders: %w", err))
 		return
 	}
 	renderPage(w, remindersTmpl, map[string]any{"Reminders": reminderRows(reminders)})