Support multiple deploy template list URLs with cross-list dedupe

Add Settings UI to configure many Portainer-format template catalogs (not just one), merge them on fetch, drop duplicates by image/stack/title, and show source counts on the Deploy view.

test/template-lists.test.js

@@ -0,0 +1,80 @@
+import test from 'brittle'
+import {
+  normalizeTemplateListUrls,
+  templateDedupeKey,
+  extractTemplatesArray,
+  mergeAndDedupeTemplates,
+  DEFAULT_TEMPLATE_LIST_URLS,
+} from '../client/templateLists.js'
+
+test('normalizeTemplateListUrls unique https only', (t) => {
+  const urls = normalizeTemplateListUrls([
+    'https://example.com/a.json',
+    'https://example.com/a.json',
+    '  https://example.com/b.json ',
+    'ftp://bad.example/c.json',
+    'not-a-url',
+    '',
+  ])
+  t.is(urls.length, 2)
+  t.ok(urls[0].includes('a.json'))
+  t.ok(urls[1].includes('b.json'))
+})
+
+test('templateDedupeKey prefers image', (t) => {
+  t.is(
+    templateDedupeKey({ title: 'App', image: 'nginx:latest' }),
+    templateDedupeKey({ title: 'Other', image: 'nginx' })
+  )
+  t.is(templateDedupeKey({ image: 'nginx:latest' }), 'image:nginx')
+})
+
+test('templateDedupeKey for stacks uses repo', (t) => {
+  const k = templateDedupeKey({
+    title: 'Stack A',
+    repository: { url: 'https://github.com/x/y', stackfile: 'docker-compose.yml' },
+  })
+  t.ok(k.startsWith('stack:'))
+  t.ok(k.includes('github.com/x/y'))
+})
+
+test('extractTemplatesArray handles shapes', (t) => {
+  t.is(extractTemplatesArray({ templates: [{ title: 'a' }] }).length, 1)
+  t.is(extractTemplatesArray([{ title: 'b' }]).length, 1)
+  t.is(extractTemplatesArray(null).length, 0)
+})
+
+test('mergeAndDedupeTemplates removes duplicates across sources', (t) => {
+  const result = mergeAndDedupeTemplates([
+    {
+      url: 'https://a.example/t.json',
+      templates: [
+        { title: 'Nginx', image: 'nginx:latest' },
+        { title: 'Redis', image: 'redis:7' },
+      ],
+    },
+    {
+      url: 'https://b.example/t.json',
+      templates: [
+        { title: 'Nginx Official', image: 'nginx' }, // dupe of first
+        { title: 'Postgres', image: 'postgres:16' },
+      ],
+    },
+    {
+      url: 'https://bad.example/t.json',
+      templates: [],
+      error: 'HTTP 404',
+    },
+  ])
+  t.is(result.templates.length, 3)
+  t.is(result.stats.duplicates, 1)
+  t.is(result.stats.fetched, 4)
+  t.is(result.stats.unique, 3)
+  t.is(result.stats.errors.length, 1)
+  t.is(result.templates[0]._sourceUrl, 'https://a.example/t.json')
+})
+
+test('default catalog is non-empty', (t) => {
+  t.ok(DEFAULT_TEMPLATE_LIST_URLS.length >= 1)
+  t.ok(DEFAULT_TEMPLATE_LIST_URLS[0].startsWith('https://'))
+})