core: support OTEL_RESOURCE_ATTRIBUTES environment variable for custom telemetry attributes

Users can now pass custom OpenTelemetry resource attributes via the OTEL_RESOURCE_ATTRIBUTES environment variable (comma-separated key=value format). These attributes are automatically included in all telemetry data sent from both the main process and workspace environments, enabling better observability integration with existing monitoring systems that rely on custom resource tags.

packages/opencode/src/effect/observability.ts

@@ -21,12 +21,29 @@ const headers = Flag.OTEL_EXPORTER_OTLP_HEADERS
     )
   : undefined
 
-function resource() {
+export function resource(): { serviceName: string, serviceVersion: string, attributes: Record<string, string> } {
   const processMetadata = ensureProcessMetadata("main")
+  const attributes: Record<string, string> = (() => {
+    const value = process.env.OTEL_RESOURCE_ATTRIBUTES
+    if (!value) return {}
+    try {
+      return Object.fromEntries(
+        value.split(",").map((entry) => {
+          const index = entry.indexOf("=")
+          if (index < 1) throw new Error("Invalid OTEL_RESOURCE_ATTRIBUTES entry")
+          return [decodeURIComponent(entry.slice(0, index)), decodeURIComponent(entry.slice(index + 1))]
+        }),
+      )
+    } catch {
+      return {}
+    }
+  })()
+
   return {
     serviceName: "opencode",
     serviceVersion: InstallationVersion,
     attributes: {
+      ...attributes,
       "deployment.environment.name": InstallationChannel,
       "opencode.client": Flag.OPENCODE_CLIENT,
       "opencode.process_role": processMetadata.processRole,