automatically install typescript into ./node_modules if missing during build

simplifies process.

.github/workflows/build-test.yml

@@ -17,7 +17,6 @@ jobs:
         with:
           node-version: 16
           cache: 'npm'
-      - run: npm ci
       - run: 'touch */*.ts'
 
       - uses: actions/setup-go@v4

Makefile

@@ -110,10 +110,12 @@ fmt:
 tswatch:
 	bash -c 'while true; do inotifywait -q -e close_write *.ts webadmin/*.ts webaccount/*.ts webmail/*.ts; make frontend; done'
 
-install-js:
+node_modules/.bin/tsc:
 	-mkdir -p node_modules/.bin
 	npm ci
 
+install-js: node_modules/.bin/tsc
+
 install-js0:
 	-mkdir -p node_modules/.bin
 	npm install --save-dev --save-exact typescript@5.1.6
@@ -133,7 +135,7 @@ webadmin/admin.js: lib.ts webadmin/api.ts webadmin/admin.ts
 webaccount/account.js: lib.ts webaccount/api.ts webaccount/account.ts
 	./tsc.sh $@ $^
 
-frontend: webadmin/admin.js webaccount/account.js webmail/webmail.js webmail/msg.js webmail/text.js
+frontend: node_modules/.bin/tsc webadmin/admin.js webaccount/account.js webmail/webmail.js webmail/msg.js webmail/text.js
 
 install-apidiff:
 	go install golang.org/x/exp/cmd/apidiff@v0.0.0-20231206192017-f3f8817b8deb

develop.txt

@@ -3,10 +3,9 @@ This file has notes useful for mox developers.
 # Building & testing
 
 For a full build, you'll need a recent Go compiler/toolchain and nodejs/npm for
-the frontend. First install frontend dependencies (typescript) with "make
-install-js". Then run "make build" to do a full build. Run "make test" to run
-the test suite. With docker installed, you can run "make test-integration" to
-start up a few mox instances, a dns server, a postfix instance, and send email
+the frontend. Run "make build" to do a full build. Run "make test" to run the
+test suite. With docker installed, you can run "make test-integration" to start
+up a few mox instances, a dns server, a postfix instance, and send email
 between them.
 
 The mox localserve command is a convenient way to test locally. Most of the