Soften the tone of the docs and comments written today

apps/web/README.md

@@ -1,4 +1,35 @@
 # web
 
-Next.js frontend. Chat UI, auth pages, citation/disclaimer rendering, session
-history. Talks only to `api-gateway` — never calls internal services directly.
+Next.js frontend: chat UI, citation/evidence panel, drug autocomplete,
+persistent clinical disclaimer banner.
+
+**Current call path: browser → this app's own route handlers → `ai-service`.**
+`api-gateway` is not built yet (its directory holds a `README.md` and a
+`package.json`), so requests go through `app/api/` and on to `ai-service`
+(`API_GATEWAY_URL ?? AI_SERVICE_URL`, set to `http://ai-service:8000` in
+production). There is no authentication layer in this path today. When the
+gateway and auth services are built, this is the seam that changes.
+
+`app/api/chat/route.ts` is more than a proxy: it maps `ai-service`'s abstain
+`reason` codes to the Vietnamese text the user reads. A reason code with no
+entry there falls back to wording that reads as "no data in the formulary",
+which would misrepresent an outage or a timeout — so a new backend reason
+code needs an entry here in the same change.
+
+Timeouts: `_components/ChatPanel.tsx` aborts a request at 65s, derived from
+the backend's ceiling (a 40s request budget that can overrun by one in-flight
+model call). A lower value can cut off answers the server has successfully
+produced, so keep it above that ceiling if it is ever revisited.
+
+## Running
+
+```powershell
+pnpm install
+pnpm --filter web dev     # http://localhost:3000, expects ai-service on :8079
+```
+
+## Tests
+
+There are none, and no test runner is configured. Verify changes by driving
+the real UI in a browser; `pytest` passing in `apps/ai-service` says nothing
+about this app.