feat: harden notification stack and switch logging selectors to icon grid

Notifications:
- Add shared http_base, redact, and SSRF hardening modules
- Refactor dispatcher, queue, receiver and per-provider clients
  (telegram, discord, email, matrix, ntfy, slack, webhook) to use
  the shared base, with bounded queue and redacted error logs
- Tests for ssrf, redact, http_base, queue bounds, dispatcher
  aggregation, telegram media partition, email and matrix clients

Frontend:
- Settings: log level / log format selectors now use IconGridSelect
  with per-option icons and i18n descriptions
- Minor providers page and entity-cache store updates

Tooling:
- Document code-review-graph MCP usage in CLAUDE.md
- Ignore .code-review-graph/, register .mcp.json

frontend/src/routes/providers/+page.svelte

@@ -3,7 +3,7 @@
 	import { slide } from 'svelte/transition';
 	import { api, getBlockedBy, type BlockedByDetail } from '$lib/api';
 	import { t } from '$lib/i18n';
-	import { providersCache } from '$lib/stores/caches.svelte';
+	import { providersCache, externalUrlCache } from '$lib/stores/caches.svelte';
 	import PageHeader from '$lib/components/PageHeader.svelte';
 	import Card from '$lib/components/Card.svelte';
 	import Loading from '$lib/components/Loading.svelte';
@@ -21,7 +21,7 @@
 	import { globalProviderFilter } from '$lib/stores/provider-filter.svelte';
 	import { topbarAction } from '$lib/stores/topbar-action.svelte';
 	import { onDestroy } from 'svelte';
-	import { snackSuccess, snackError } from '$lib/stores/snackbar.svelte';
+	import { snackSuccess, snackError, snackInfo } from '$lib/stores/snackbar.svelte';
 	import { highlightFromUrl } from '$lib/highlight';
 	import { getDescriptor, buildProviderFormDefaults } from '$lib/providers';
 	import Button from '$lib/components/Button.svelte';
@@ -45,6 +45,30 @@
 	let confirmDelete = $state<ServiceProvider | null>(null);
 
 	let descriptor = $derived(getDescriptor(form.type));
+	let externalUrl = $derived(externalUrlCache.value);
+
+	function buildWebhookUrl(pattern: string, token: string): string {
+		const path = pattern.replace('{token}', token ?? '');
+		return externalUrl ? `${externalUrl}${path}` : path;
+	}
+
+	function copyWebhookUrl(e: Event, url: string) {
+		e.preventDefault();
+		e.stopPropagation();
+		if (navigator.clipboard?.writeText) {
+			navigator.clipboard.writeText(url);
+		} else {
+			const ta = document.createElement('textarea');
+			ta.value = url;
+			ta.style.position = 'fixed';
+			ta.style.opacity = '0';
+			document.body.appendChild(ta);
+			ta.select();
+			document.execCommand('copy');
+			document.body.removeChild(ta);
+		}
+		snackInfo(`${t('snack.copied')}: ${url}`);
+	}
 
 	// Auto-update name when provider type changes (unless user manually edited)
 	$effect(() => {
@@ -76,6 +100,7 @@
 			onclick: () => { showForm ? (showForm = false, editing = null) : openNew(); },
 		});
 		load();
+		externalUrlCache.fetch().catch(() => { /* fall back to relative URLs */ });
 	});
 	onDestroy(() => topbarAction.clear());
 	async function load() {
@@ -246,9 +271,15 @@
 			</div>
 			{/each}
 			{#if descriptor?.webhookUrlPattern && editing}
+			{@const editingWebhookUrl = buildWebhookUrl(descriptor.webhookUrlPattern, providers.find(p => p.id === editing)?.webhook_token ?? '')}
 			<div class="bg-[var(--color-muted)] rounded-md p-3">
 				<div class="block text-sm font-medium mb-1">{t('providers.webhookUrl')}</div>
-				<code class="text-xs select-all break-all">{descriptor.webhookUrlPattern.replace('{token}', providers.find(p => p.id === editing)?.webhook_token ?? '')}</code>
+				<button type="button"
+					onclick={(e) => copyWebhookUrl(e, editingWebhookUrl)}
+					title={t('providers.webhookUrlCopyTitle')}
+					class="text-xs break-all text-left hover:text-[var(--color-primary)] cursor-pointer font-mono w-full">
+					<code class="bg-transparent">{editingWebhookUrl}</code>
+				</button>
 				<p class="text-xs text-[var(--color-muted-foreground)] mt-1">{t('providers.webhookUrlHint')}</p>
 			</div>
 			{/if}
@@ -295,7 +326,14 @@
 								<p class="text-xs text-[var(--color-muted-foreground)] font-mono">{provider.config.host}:{provider.config.port || 3493}</p>
 							{/if}
 							{#if provDesc?.webhookUrlPattern}
-								<p class="text-xs text-[var(--color-muted-foreground)] font-mono mt-0.5">{t('providers.webhookUrl')}: <span class="select-all">{provDesc.webhookUrlPattern.replace('{token}', provider.webhook_token)}</span></p>
+								{@const webhookUrl = buildWebhookUrl(provDesc.webhookUrlPattern, provider.webhook_token)}
+								<p class="text-xs text-[var(--color-muted-foreground)] font-mono mt-0.5">
+									{t('providers.webhookUrl')}:
+									<button type="button"
+										onclick={(e) => copyWebhookUrl(e, webhookUrl)}
+										title={t('providers.webhookUrlCopyTitle')}
+										class="hover:text-[var(--color-primary)] cursor-pointer break-all text-left">{webhookUrl}</button>
+								</p>
 							{/if}
 						</div>
 					</div>

frontend/src/routes/settings/+page.svelte

@@ -12,7 +12,10 @@
 	import ConfirmModal from '$lib/components/ConfirmModal.svelte';
 	import LocaleSelector from '$lib/components/LocaleSelector.svelte';
 	import TimezoneSelector from '$lib/components/TimezoneSelector.svelte';
+	import IconGridSelect from '$lib/components/IconGridSelect.svelte';
+	import { logLevelItems, logFormatItems } from '$lib/grid-items';
 	import { snackSuccess, snackError } from '$lib/stores/snackbar.svelte';
+	import { externalUrlCache } from '$lib/stores/caches.svelte';
 
 	interface CacheBucketStats {
 		count: number;
@@ -76,6 +79,7 @@
 		saving = true; error = '';
 		try {
 			settings = await api('/settings', { method: 'PUT', body: JSON.stringify(settings) });
+			externalUrlCache.invalidate();
 			snackSuccess(t('settings.saved'));
 		} catch (err: any) { error = err.message; snackError(err.message); }
 		saving = false;
@@ -221,21 +225,11 @@
 			<div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
 				<div>
 					<label class="block text-xs font-medium mb-1">{t('settings.logLevel')}<Hint text={t('settings.logLevelHint')} /></label>
-					<select bind:value={settings.log_level}
-						class="w-full px-3 py-1.5 text-sm border border-[var(--color-border)] rounded-md bg-[var(--color-background)]">
-						<option value="DEBUG">DEBUG</option>
-						<option value="INFO">INFO</option>
-						<option value="WARNING">WARNING</option>
-						<option value="ERROR">ERROR</option>
-					</select>
+					<IconGridSelect items={logLevelItems()} bind:value={settings.log_level} columns={2} />
 				</div>
 				<div>
 					<label class="block text-xs font-medium mb-1">{t('settings.logFormat')}<Hint text={t('settings.logFormatHint')} /></label>
-					<select bind:value={settings.log_format}
-						class="w-full px-3 py-1.5 text-sm border border-[var(--color-border)] rounded-md bg-[var(--color-background)]">
-						<option value="text">text</option>
-						<option value="json">json</option>
-					</select>
+					<IconGridSelect items={logFormatItems()} bind:value={settings.log_format} columns={2} />
 				</div>
 				<div class="sm:col-span-2">
 					<label class="block text-xs font-medium mb-1">{t('settings.logLevels')}<Hint text={t('settings.logLevelsHint')} /></label>