docs: document EAS update --platform gotcha and node_modules corruption fix

Two Known-Issues entries from tonight's OTA-publish session:
- eas update needs --platform android explicitly (no web target/
  react-native-web in this project, --platform all fails bundling)
- mobile/node_modules can end up with silently missing nested files after
  a bad install, invisible to npm install itself (seen across @expo/cli,
  @sentry/browser, @sentry-internal/browser-utils in the same session) -
  full rm -rf node_modules && npm install is the fix, not a targeted one

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -525,3 +525,5 @@ npx vitest              # watch mode
 | `CRON_SECRET` must be set for all cron routes | Without it, the routes return 401 and nothing fires — there is no serverless scheduler here, an external trigger (NAS crontab) is required. |
 | Server-side requests to the app's own domain must target the DDNS hostname, not `pawfeed.org` | Nginx Proxy Manager's origin TLS certificate is only valid for `pawfeed.neodk.ipv64.de` — `pawfeed.org` works for browsers only because Cloudflare terminates TLS at the edge and doesn't strictly verify the origin cert. A plain `curl https://pawfeed.org/...` from the NAS itself (e.g. `docker/run-cron.sh`) fails with an SSL hostname mismatch; use `curl --resolve pawfeed.neodk.ipv64.de:443:127.0.0.1 https://pawfeed.neodk.ipv64.de/...` instead. |
 | A 401 (not 403) from an admin tRPC procedure usually means a stale Clerk session, not a permissions bug | `protectedProcedure` throws `UNAUTHORIZED` (401) when Clerk's session is missing/expired; `assertAdmin()` throws `FORBIDDEN` (403) when the session is valid but the role is too low. A browser tab left open and backgrounded for hours can let Clerk's silent token refresh lapse — reload the page before suspecting a code regression. |
+| `eas update` must be run with `--platform android` (`mobile/`), not `--platform all` | This app has no web target — `react-native-web` isn't installed — so the default `--platform all` fails bundling with `Unable to resolve module react-native-web/dist/index`. Previously published updates were all Android-only too (check `eas channel:view <channel>` to confirm before assuming this changed). |
+| `mobile/node_modules` can end up silently corrupted (missing nested files) after an interrupted/partial install, without `npm install` re-detecting or fixing it | Symptom: Metro bundling fails with `Unable to resolve module ./some/nested/path.js` inside an already-installed package (seen with `@expo/cli`'s `utils/telemetry`, then `@sentry/browser` and `@sentry-internal/browser-utils` in the same session) — `npm install` reports "up to date" and does nothing. Fix: `rm -rf node_modules && npm install` (a full reinstall), not a targeted one; deleting just the one broken package's folder can just surface the *next* corrupted package one bundle-failure at a time. |