add "reject quotes" toggle at user and instance level

+ improve, cleanup, and de-duplicate quote resolution
+ add warning message when quote cannot be loaded
+ add "process error" framework to display warnings when a note cannot be correctly loaded from another instance

packages/frontend/src/components/SkErrorList.vue

@@ -0,0 +1,43 @@
+<!--
+SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<!-- Match appearance of MkRemoteCaution.vue -->
+<div v-for="error of displayErrors" :key="error" :class="$style.root">
+	<i :class="$style.icon" class="ti ti-alert-triangle"></i>{{ i18n.ts._processErrors[error] ?? error }}
+</div>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue';
+import { i18n } from '@/i18n.js';
+
+const props = defineProps<{
+	errors?: string[] | null;
+}>();
+
+const displayErrors = computed<Iterable<string>>(() => {
+	if (!props.errors?.length) return [];
+
+	// Set constructor preserve order, so we can sort first to avoid a copy operation.
+	return new Set(props.errors.toSorted());
+});
+</script>
+
+<style module lang="scss">
+.root {
+	font-size: 0.8em;
+	padding: 16px;
+	background: color-mix(in srgb, var(--MI_THEME-infoWarnBg) 65%, transparent);
+	color: var(--MI_THEME-infoWarnFg);
+	border-radius: var(--MI-radius);
+	overflow: clip;
+	z-index: 1;
+}
+
+.icon {
+	margin-right: 8px;
+}
+</style>