docs(nodejs): drop stale OPENTELEMETRY_JS_PATH and IITM_PATH refs

Build scripts only consume OPENTELEMETRY_JS_CONTRIB_PATH now; the
upstream opentelemetry-js and import-in-the-middle forks were dropped
when we moved those deps to npm.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: jmsundar

nodejs/README.md

@@ -12,27 +12,17 @@ included and loaded automatically if you use the AWS SDK v2.
 
 ### Requirements
 
-You will need to provide the path to 3 forked dependencies through environment
-variables for the libraries below:
+The build only needs one forked dependency:
 
-- opentelemetry-js: `OPENTELEMETRY_JS_PATH`.
-- opentelemetry-js-contrib: `OPENTELEMETRY_JS_CONTRIB_PATH`.
-- import-in-the-middle: `IITM_PATH`.
+- `coralogix/opentelemetry-js-contrib` (branch `coralogix-autoinstrumentation`), pointed at by `OPENTELEMETRY_JS_CONTRIB_PATH`.
 
-Note that these paths are very important, because they are will impact the
-relative paths in some `package.json` files in ways that could potentially
-break CI scripts.
-
-To avoid this issue we recommend setting them like so:
+If you already have a local checkout, set:
 
 ```sh
 export OPENTELEMETRY_JS_CONTRIB_PATH=./opentelemetry-js-contrib-cx
-export OPENTELEMETRY_JS_PATH=./opentelemetry-js
-export IITM_PATH=./import-in-the-middle
 ```
 
-This project's `.gitignore` is already configured with these folders
-to ensure your git index stays clean.
+Otherwise leave it unset and `./scripts/build-nodejs.sh` will clone the pinned SHA to `.build-cache/opentelemetry-js-contrib/`. Both paths are gitignored. `upstream/opentelemetry-js` and `import-in-the-middle` are now resolved from npm, no local checkout needed.
 
 ### The layer
 
@@ -43,8 +33,4 @@ the root of the application:
 ./scripts/build-nodejs.sh
 ```
 
-This is a thin wrapper over `./scripts/build_nodejs_layer.sh` that
-will clone the forked dependencies if the paths indicated by the
-previously mentioned environment variables are empty, then use
-that script to download all dependencies and compile all code.
-The layer zip file will be present at `./packages/layer/build/layer.zip`.
+This is a thin wrapper over `./scripts/build_nodejs_layer.sh` that handles the cx-contrib fork clone/checkout when `OPENTELEMETRY_JS_CONTRIB_PATH` is unset, then calls `build_nodejs_layer.sh` to install deps and compile. The layer zip file will be present at `./packages/layer/build/layer.zip`.