fix(run-engine): don't mislabel DB errors as UnclassifiableWaitpointId in completeWaitpoint

forWaitpointCompletion resolves the owning store by probing the database, so a
transient DB/infra error surfaced from that call was being caught and rethrown
as UnclassifiableWaitpointId with a misleading "length matches neither cuid nor
run-ops id" message, losing the original error's type, retryability, and error
grouping.

Narrow the catch so only a genuine id-classification failure (UnclassifiableRunId)
becomes UnclassifiableWaitpointId; every other error (including DB connectivity
failures) is rethrown unchanged.

internal-packages/run-engine/src/engine/systems/waitpointSystem.ts

@@ -1,5 +1,5 @@
 import { timeoutError, tryCatch } from "@trigger.dev/core/v3";
-import { WaitpointId } from "@trigger.dev/core/v3/isomorphic";
+import { UnclassifiableRunId, WaitpointId } from "@trigger.dev/core/v3/isomorphic";
 import type {
   PrismaClientOrTransaction,
   TaskRun,
@@ -91,11 +91,24 @@ export class WaitpointSystem {
     try {
       store = await this.$.runStore.forWaitpointCompletion(id, { routeKind: "MANUAL" });
     } catch (error) {
-      this.$.logger.error("completeWaitpoint: unclassifiable waitpointId", {
+      // Only a genuine id-classification failure should become UnclassifiableWaitpointId.
+      // forWaitpointCompletion also probes the DB to resolve the owning store, so a transient
+      // database/infra error (e.g. can't reach the database) can surface here too. Those MUST
+      // bubble up unchanged so they keep their original type, retryability, and error grouping
+      // instead of being mislabelled as an unclassifiable id.
+      if (error instanceof UnclassifiableRunId) {
+        this.$.logger.error("completeWaitpoint: unclassifiable waitpointId", {
+          waitpointId: id,
+          error,
+        });
+        throw new UnclassifiableWaitpointId(id, { cause: error });
+      }
+
+      this.$.logger.error("completeWaitpoint: error resolving waitpoint store", {
         waitpointId: id,
         error,
       });
-      throw new UnclassifiableWaitpointId(id, { cause: error });
+      throw error;
     }
 
     // 1. Complete the Waitpoint (if not completed)