fix(web): review-round attachment refinements

Body-portal the lightbox and toast so transformed ancestors cannot trap
their fixed positioning (a lightbox opened from a chat message covered only
the chat column); make the toast pointer-transparent; observe the rail
element's own size instead of window resizes; consume vertical wheel ticks
exclusively via a non-passive listener with LINE/PAGE delta normalization;
keep the start position when the rail mounts over an existing draft; honor
prefers-reduced-motion for the toast, remove-control, and paging; retry
loads through the guarded load effect; note the deliberate promptError
re-announce; pin the intake toast in the assembled snapshot; sync the
superseded multimodal note and package docs.

packages/client/ui-attachment/package.json

@@ -30,12 +30,14 @@
     "@deepseek-ai/dsh-attachment": "workspace:^",
     "@deepseek-ai/dsh-client-ui-primitives": "workspace:^",
     "clsx": "^2.0.0",
-    "react": "^18.2.0"
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0"
   },
   "devDependencies": {
     "@deepseek-ai/cordis": "workspace:^",
     "@deepseek-ai/dsh-invariants": "workspace:^",
-    "@types/react": "~18.3.1"
+    "@types/react": "~18.3.1",
+    "@types/react-dom": "~18.3.0"
   },
   "files": [
     "lib/index.js",