Send overall job status in init-post status report (#2097)

Co-authored-by: Henry Mercer <henry@henrymercer.name>

src/environment.ts

@@ -1,3 +1,9 @@
+/**
+ * Environment variables used by the CodeQL Action.
+ *
+ * We recommend prefixing environment variables with `CODEQL_ACTION_`
+ * to reduce the risk that they are overwritten by other steps.
+ */
 export enum EnvVar {
   /** Whether the `analyze` Action completes successfully. */
   ANALYZE_DID_COMPLETE_SUCCESSFULLY = "CODEQL_ACTION_ANALYZE_DID_COMPLETE_SUCCESSFULLY",
@@ -35,6 +41,9 @@ export enum EnvVar {
   /** UUID representing the current job run. */
   JOB_RUN_UUID = "JOB_RUN_UUID",
 
+  /** Status for the entire job, submitted to the status report in `init-post` */
+  JOB_STATUS = "CODEQL_ACTION_JOB_STATUS",
+
   ODASA_TRACER_CONFIGURATION = "ODASA_TRACER_CONFIGURATION",
 
   /**