perf: drop livechat sourcemaps from meteor bundle and clean dist on build

The livechat widget's webpack build emits full source-map files (~12 MB
in a fresh build, far more with accumulated rebuilds). They are copied
into apps/meteor/public/livechat/ by the rocketchat-livechat plugin and
end up in the Meteor bundle and Docker image without adding runtime
value.

- plugin/build.sh: delete .map files after copying dist into public.
  Maps remain in packages/livechat/dist for local debugging or upload
  to error tracking.
- packages/livechat: prefix build with yarn clean so dist no longer
  accumulates stale hashed chunks across rebuilds (noticed dist growing
  to ~500 MB locally vs. ~18 MB fresh).

Author: ggazzo

apps/meteor/packages/rocketchat-livechat/plugin/build.sh

@@ -16,6 +16,10 @@ echo "Installing Livechat ${LATEST_LIVECHAT_VERSION}..."
 cd $LIVECHAT_DIR
 
 cp -a $ROOT/../../packages/livechat/dist/. ./
+# Sourcemaps remain in packages/livechat/dist for local debugging / upload
+# to error tracking, but should not be baked into the Meteor bundle and
+# Docker image (they account for ~360 MB of the shipped widget).
+find . -name '*.map' -delete
 # change to lowercase so all injected junk from rocket.chat is not sent: https://github.com/meteorhacks/meteor-inject-initial/blob/master/lib/inject-core.js#L10
 # this is not harmful since doctype is case-insesitive: https://www.w3.org/TR/html5/syntax.html#the-doctype
 meteor node -e 'fs.writeFileSync("index.html", fs.readFileSync("index.html").toString().replace("<!DOCTYPE", "<!doctype"));'

packages/livechat/package.json

@@ -12,7 +12,7 @@
 		"/build"
 	],
 	"scripts": {
-		"build": "cross-env TS_NODE_PROJECT=\"tsconfig.webpack.json\" webpack-cli --mode production",
+		"build": "yarn clean && cross-env TS_NODE_PROJECT=\"tsconfig.webpack.json\" webpack-cli --mode production",
 		"build-storybook": "storybook build",
 		"clean": "rimraf dist",
 		"dev": "yarn build",