feat: support npm workspaces for local development

Add workspaces configuration and workspace-aware scripts for developing
with local packages (such as frontend-base).  Decouple clean from build
in the Makefile so watch mode can rebuild without wiping dist/.

Part of openedx/frontend-base#184

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: arbrandes

.gitignore

@@ -3,6 +3,9 @@ npm-debug.log
 coverage
 module.config.js
 dist/
+packages/
+/.turbo
+/turbo.json
 /*.tgz
 
 ### i18n ###

Makefile

@@ -10,6 +10,8 @@ transifex_input = $(i18n)/transifex_input.json
 # This directory must match .babelrc .
 transifex_temp = ./temp/babel-plugin-formatjs
 
+TURBO = TURBO_TELEMETRY_DISABLED=1 turbo --dangerously-disable-package-manager-check
+
 NPM_TESTS=build i18n_extract lint test
 
 # Variables for additional translation sources and imports (define in edx-internal if needed)
@@ -29,10 +31,27 @@ test.npm.%: validate-no-uncommitted-package-lock-changes
 requirements:  ## install ci requirements
 	npm ci
 
+# turbo.site.json is the standalone turbo config for this package.  It is
+# renamed to avoid conflicts with turbo v2's workspace validation, which
+# rejects root task syntax (//#) and requires "extends" in package-level
+# turbo.json files, such as when running in a site repository. The targets
+# below copy it into place before running turbo and clean up after.
+turbo.json: turbo.site.json
+	cp $< $@
+
+build-packages: turbo.json
+	$(TURBO) run build; rm -f turbo.json
+
+clean-packages: turbo.json
+	$(TURBO) run clean; rm -f turbo.json
+
+dev-packages: turbo.json
+	$(TURBO) run watch:build dev:site; rm -f turbo.json
+
 clean:
 	rm -rf dist
 
-build: clean
+build:
 	tsc --project tsconfig.build.json
 	find src -type f \( -name '*.scss' -o \( \( -name '*.png' -o -name '*.svg' \) -path '*/assets/*' \) \) -exec sh -c '\
 	  for f in "$$@"; do \

nodemon.json

@@ -0,0 +1,6 @@
+{
+  "watch": [
+    "src"
+  ],
+  "ext": "js,jsx,ts,tsx,scss,png,svg"
+}