ref(node)!: Remove @opentelemetry/instrumentation dependency

`@sentry/node` was the last package holding `@opentelemetry/instrumentation`.
All instrumentation is now channel-based via orchestrion, so the surface this
dependency backed is dead or a no-op:

- `generateInstrumentOnce` (and the framework re-exports) had no call sites.
- `ensureIsWrapped`'s shimmer-based check can no longer detect channel-based
  express/koa/hapi, so its warning and the `missing_instrumentation` context
  were removed, along with the `disableInstrumentationWarnings` option and the
  `MissingInstrumentationContext` type.
- The `@sentry/node/import` ESM hook now only registers the orchestrion
  diagnostics-channel injection; the legacy iitm `@sentry/node/loader` entry
  was removed.

Adds the `makeOrchestrionLoader` rollup util (import-only, delegates to
`@sentry/server-utils/orchestrion/import-hook`). The legacy `makeOtelLoaders`
util is kept temporarily so the framework SDKs still build until they migrate
in the following PRs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: andreiborza

MIGRATION.md

@@ -304,6 +304,7 @@ Affected SDKs: `@sentry/cloudflare`.
 
 - The internal, deprecated `addAutoIpAddressToUser` export was removed.
 - The `createSpanEnvelope` function and the `SpanEnvelope` / `SpanItem` types were removed. They existed only to send standalone (v1) spans as their own segment envelope, which the SDK no longer does. Standalone spans are gone; spans are sent either on their transaction or, with span streaming, as streamed spans (`StreamedSpanEnvelope`).
+- The `disableInstrumentationWarnings` option and the `MissingInstrumentationContext` type were removed. Now that instrumentation is channel-based, the SDK can no longer detect the "you imported a framework before `Sentry.init()`" case, so the warning it gated and the context it attached no longer exist.
 - The deprecated `sendDefaultPii` option was removed. Use [`dataCollection`](#senddefaultpii-is-replaced-by-datacollection) instead.
 - The `_experiments.enableMetrics` and `_experiments.beforeSendMetric` options were removed, use the top-level `enableMetrics` and `beforeSendMetric` options instead.
 
@@ -396,6 +397,8 @@ Sentry.init({
 - The deprecated `prismaInstrumentation` option was removed. It was no longer used, as Prisma works out of the box.
 - The `registerEsmLoaderHooks` option was removed. All instrumentation is now channel-based (via `@sentry/server-utils`), so the SDK no longer registers `import-in-the-middle` ESM loader hooks and the option no longer had any effect.
 - The deprecated `SentryHttpInstrumentation` and `SentryNodeFetchInstrumentation` exports were removed. Use `instrumentHttpOutgoingRequests()` and the `nativeNodeFetchIntegration` respectively.
+- The `generateInstrumentOnce` export was removed (from `@sentry/node` and the framework SDKs that re-exported it). It wrapped OpenTelemetry's `registerInstrumentations` and is no longer needed now that instrumentation is channel-based.
+- The `@sentry/node/loader` entry point was removed. It only re-exported the `import-in-the-middle` ESM `load`/`resolve` hooks, which are unused now that Node's `--loader` flag is obsolete (minimum Node is 20.19.0) and instrumentation is channel-based. Use `node --import @sentry/node/import` instead.
 - (Fastify) The deprecated `setShouldHandleError` method was removed.
 - (AWS Lambda) The deprecated `disableAwsContextPropagation` option was removed. It no longer had any effect.
 - (AWS Lambda) The deprecated `startTrace` option was removed. It no longer had any effect; to disable tracing, set `tracesSampleRate` to `0`.

dev-packages/e2e-tests/test-applications/node-express-incorrect-instrumentation/.gitignore

@@ -0,0 +1 @@
+import '@sentry/server-utils/orchestrion/import-hook';

dev-packages/e2e-tests/test-applications/node-express-incorrect-instrumentation/package.json

@@ -282,3 +282,53 @@ export function makeOtelLoaders(outputFolder, hookVariant, options = {}) {
     },
   ]);
 }
+
+/**
+ * Emits the `@sentry/<framework>/import` entry (`build/import-hook.mjs`) as part of the rollup build,
+ * used as `node --import @sentry/<framework>/import app.js`. The generated hook imports
+ * `@sentry/server-utils/orchestrion/import-hook`, which registers the orchestrion
+ * diagnostics-channel injection, so the consuming package must declare `@sentry/server-utils` as a
+ * dependency.
+ *
+ * @param {string} outputFolder Build output folder.
+ */
+export function makeOrchestrionLoader(outputFolder) {
+  const expectedImportHookLocation = `${outputFolder}/import-hook.mjs`;
+  const foundImportHookExport = Object.keys(packageDotJSON.exports ?? {}).some(key => {
+    return packageDotJSON?.exports?.[key]?.import?.default === expectedImportHookLocation;
+  });
+  if (!foundImportHookExport) {
+    throw new Error(
+      `You used the makeOrchestrionLoader() rollup utility without specifying the import hook inside \`exports[something].import.default\`. Please add "${expectedImportHookLocation}" as a value there (maybe check for typos - it needs to be "${expectedImportHookLocation}" exactly).`,
+    );
+  }
+
+  const requiredDep = '@sentry/server-utils';
+  const foundRequiredDep =
+    Object.keys(packageDotJSON.dependencies ?? {}).some(key => {
+      return key === requiredDep;
+    }) ||
+    Object.keys(packageDotJSON.devDependencies ?? {}).some(key => {
+      return key === requiredDep;
+    });
+
+  if (!foundRequiredDep) {
+    throw new Error(
+      `You used the makeOrchestrionLoader() rollup utility but didn't specify the "${requiredDep}" dependency in ${path.resolve(
+        process.cwd(),
+        'package.json',
+      )}. Please add it to the dependencies.`,
+    );
+  }
+
+  return defineConfig([
+    {
+      input: path.join(__dirname, 'code', 'importHookTemplate.js'),
+      external: /.*/,
+      output: {
+        format: 'esm',
+        file: path.join(outputFolder, 'import-hook.mjs'),
+      },
+    },
+  ]);
+}