CI: rebalance integration and Postman shards to cut PR wall clock

Problem

A PR pipeline run takes 74–103m of wall clock. The structural floor is ~54m:

Initial Artifact Build   15m   (serial prefix -- every test job waits on it)
slowest test job         39m
                        ----
floor                    54m

Everything above that floor is queue time (one run fans out ~26 jobs / ~587 job-minutes; one observed run accumulated 271 job-minutes of queue, with individual jobs waiting 20m).

The floor itself is set by the slowest single test job, and two jobs were tied at the top:

Because they are nearly equal, rebalancing either one alone moves wall clock by ~1 minute — the other immediately becomes the tail. They have to be fixed together.

Two further findings from measuring:

1. GraphQLTests is a single 25.6m collection. With ~9.4m of fixed cost per Postman shard, no amount of regrouping gets Postman below ~35m. It is the binding constraint on the entire pipeline.
2. The build-classes artifact is uploaded on every build and consumed by nothing. It costs ~0.5m on the serial critical path. The only restore-classes: true caller is deploy-javadoc, which no workflow invokes.

Scope

• Rebalance integration shards on measured per-class time rather than class count (class count is a poor proxy — one shard held 298 classes/31m, another 52 classes/14m).
• Rebalance Postman groups on measured newman time, and shard GraphQLTests by folder rather than splitting the 518KB collection file.
• Merge the Postman micro-groups that are ~85% fixed overhead.
• Delete the dead build-classes artifact.
• Hold total job count flat so this does not add queue pressure.

Out of scope

Queue time — the dominant term above the 54m floor. Reducing it needs either runner capacity or fewer jobs, and is worth measuring separately once the tail is down.

Acceptance

• Slowest test job drops from ~39m to ~26m.
• Total job count unchanged.
• No test is dropped, duplicated, or silently skipped.

Start by locating the CI workflow definitions for the integration and Postman shards, then trace the build-classes artifact and its only named consumer, deploy-javadoc. Rebalance using the measured test times and verify that the slowest job is about 26 minutes, job count stays unchanged, and no tests are dropped, duplicated, or skipped.