docs: fix frontend deploy instructions — rsync dist/, not the repo root

The previous deploy snippet rsync'd the UI repo root (excluding dist/),
which pushed the Vite DEV index.html (<script src=/src/main.tsx>) to
production and rendered a blank page. Correct to build then rsync the
dist/ output with --delete.

docs/INSTALL.md

@@ -201,12 +201,12 @@ npm install
 npm run build                       # outputs dist/
 ```
 
-Deploy the static build to the web root (Apache serves it and proxies `/api/`
-to :8098 and `/audio/` to :8099):
+Deploy the **`dist/` output** (not the repo root) to the web root — the root
+`index.html` is the Vite *dev* entry (`<script src="/src/main.tsx">`) and would
+render a blank page in production:
 
 ```bash
-sudo -A rsync -a --exclude node_modules --exclude dist \
-     /home/jp/Work/voicemail-ui/ /home/txt3/domains/vm.txt3.net/public_html/
+sudo rsync -a --delete dist/ /home/txt3/domains/vm.txt3.net/public_html/
 ```
 
 Keep this repo's copy in sync for documentation/commit purposes: