fix(viewer): the Clickable surfaces toggle never reached the request

Ticking it did nothing: the reconvert ran and reported success, and the GLB came back with
no face regions. My own bug, from the commit that added the toggle.

reconvert() reads faceRegionsOn but the useCallback dep array listed only
[current, reconverting, serializerSel]. So the memoized callback kept the closure from an
earlier render, where faceRegionsOn was false, and sent extraOptions: undefined however the
checkbox was set.

Confirmed against the deployment before fixing: audit 88603's reconvert GLB carries
id_hierarchy + draw_ranges_node0 and no face_ranges, while POSTing the same job to the same
API with conversion_options {"face_regions": true} produces face_ranges_node0. The backend
chain — allowlist (face_regions is in ConverterRegistry.all_options), worker _env_map_full,
ADA_STREAM_TESS_FACE_REGIONS, native_step_to_glb — was doing its job the whole way.

react-hooks/exhaustive-deps is exactly the rule that catches this, and it never ran: eslint
isn't configured for this package (v9 wants a flat config; `npx eslint` only prints the
migration guide), so every dep array here is hand-maintained. Worth wiring up separately —
this class of bug is silent by construction, and no test in this suite can see it (the
frontend tests are node --test over pure modules, with no React renderer).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Krande

src/frontend/src/components/viewer/GalleryControls.tsx

@@ -266,7 +266,12 @@ const GalleryControls: React.FC = () => {
         } finally {
             setReconverting(false);
         }
-    }, [current, reconverting, serializerSel]);
+        // faceRegionsOn belongs here: without it useCallback hands back a closure that captured the
+        // value from an earlier render, so ticking the toggle re-renders but the memoized reconvert
+        // still sends the old answer — the request goes out without face_regions and the conversion
+        // reports success. react-hooks/exhaustive-deps would have caught it; eslint isn't wired up
+        // for this package, so these arrays are hand-maintained.
+    }, [current, reconverting, serializerSel, faceRegionsOn]);
 
     // NOTE: every hook must be declared before the `if (!enabled) return null` early return below —
     // React counts hooks per render, so a hook after the return changes the count when the gallery is