Withhold recipe source urls whose host the browser cannot parse

safeSourceURL accepted hosts that Go's url.Parse takes but the browser's
URL parser refuses, such as "https://[bad]/curry", so the detail API could
send a source.url that sourceUrl() in web/src/dinners/detail.ts rejects,
failing the whole recipe screen. The server now also requires a host the
browser parses as it stands: a bracketed host must be an IPv6 address
without a zone; any other must be ASCII letters, digits and hyphens in
non-empty dot-separated labels, with no punycode label and, when its last
label is a number, a valid dotted quad; and the host must be spelled out,
not percent-encoded. Any other link is withheld as before.

web/src/dinners/testdata/source_url_cases.json pins the source object
the handler sends for each stored link. The Go server test checks the
handler against it, and the recipe screen test renders each source from
it, so the two parsers cannot drift apart on those links.

Task: c1a97243-3e41-42fc-a1a0-1ac684ccb463

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/dinners/DinnerDetailPage.test.tsx

@@ -9,6 +9,7 @@ import { errorResponse, jsonResponse, stubFetchByPath } from '../test/fetchStub.
 import { mockViewport } from '../test/matchMedia.ts'
 import { GROUNDING_POLL_MS } from './api.ts'
 import { DinnerDetailPage, REGULAR_DINNERS } from './DinnerDetailPage.tsx'
+import sourceCases from './testdata/source_url_cases.json'
 
 const DINNER = '/api/v1/dinners/d1'
 
@@ -186,6 +187,23 @@ describe('DinnerDetailPage', () => {
       expect(screen.queryByRole('link', { name: /Recipe from/ })).not.toBeInTheDocument()
     })
 
+    // Each source exactly as the Go handler sends it for a stored link
+    // (internal/server's TestGetDinnerSourceURLOnlyWhenSafe checks the same
+    // file), so every url the server sends must parse here.
+    it.each(sourceCases.cases)('renders the source the server sends for $stored', async ({ source }) => {
+      serve(detail({ source }))
+      renderAt(['/dinner/d1'])
+
+      const credit = await screen.findByText('Recipe from Curry House')
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+      if (source.url === null) {
+        expect(credit.closest('a')).toBeNull()
+        expect(screen.queryByRole('link', { name: /Recipe from/ })).not.toBeInTheDocument()
+      } else {
+        expect(screen.getByRole('link', { name: 'Recipe from Curry House' })).toHaveAttribute('href', new URL(source.url).href)
+      }
+    })
+
     it('leaves the credit out when the server names no site', async () => {
       serve(detail({ source: { site_name: null } }))
       renderAt(['/dinner/d1'])

web/src/dinners/testdata/source_url_cases.json

@@ -0,0 +1,52 @@
+{
+  "cases": [
+    {
+      "stored": "https://kitchen.example/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": "https://kitchen.example/recipes/chicken-curry" }
+    },
+    {
+      "stored": "https://Kitchen-2.Example.com.:8443/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": "https://Kitchen-2.Example.com.:8443/recipes/chicken-curry" }
+    },
+    {
+      "stored": "https://[2001:db8::1]/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": "https://[2001:db8::1]/recipes/chicken-curry" }
+    },
+    {
+      "stored": "https://192.0.2.7/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": "https://192.0.2.7/recipes/chicken-curry" }
+    },
+    {
+      "stored": "https://[bad]/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "https://[fe80::1%25en0]/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "https://192.0.2.999/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "https://xn--a.example/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "https://kitchen.example/recipes/chicken-curry?access_token=query-token",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "https://user-token@kitchen.example/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "http://kitchen.example/recipes/chicken-curry",
+      "source": { "site_name": "Curry House", "url": null }
+    },
+    {
+      "stored": "https://kitchen.example/recipes/chicken-curry#token=fragment-token",
+      "source": { "site_name": "Curry House", "url": null }
+    }
+  ]
+}