Image #40 logs showed three "Failed to load image" errors for
api.openverse.org/...thumb/ URLs even though the search-pipeline
successfully fetched URLs from openverse via the dev server (the
HTTPS_PROXY fix from 3a6f8480 routes server-side fetches through the
local proxy). The browser-side image loader doesn't go through the
same dispatcher: \`new Image(); img.src = url\` does a direct
browser fetch that ignores HTTP_PROXY env vars, so on a machine that
requires the proxy to reach openverse.org the canvas paints the
placeholder visual even though the search-pipeline already found a
valid image URL.
New endpoint \`/api/ai/image-proxy?url=<encoded-url>\`:
- Proxies image bytes through the dev server.
- Reuses \`configureProxyDispatcher\` so the upstream fetch routes
through HTTPS_PROXY (same path as image-search).
- Allow-lists known image hosts (openverse, wikimedia, flickr's
static CDN) to prevent the dev server being used as an open
proxy. Unknown hosts get 403.
- Forwards Content-Type and Cache-Control from upstream.
- Sets Access-Control-Allow-Origin: * so canvas readback works.
\`mapOpenverseResult\` and \`mapWikimediaPages\` now return thumbUrl
wrapped via \`viaImageProxy(externalUrl)\`. The browser fetches
\`/api/ai/image-proxy?url=...\` (same-origin, no proxy needed),
the server fetches the upstream (with proxy), bytes flow back,
the canvas paints the photo. Test expectations updated to assert
the proxy wrapper.
Net effect: with HTTPS_PROXY set, image search end-to-end (search
results found AND images actually load in canvas) works on
proxy-required dev machines. With no proxy env var set
(production / CI), the cascade is still well-behaved — proxy
dispatcher is a no-op, server fetch is direct, no proxy wrapping
is necessary but it doesn't hurt either (the endpoint just adds
a hop).