[soltros]

Graphics and mesh program selection cache a not-ready Program before preparing its background job. If state/code copying, capture allocation or enqueueing throws, the cached Program has no job to complete it: subsequent selection returns that pending entry and a draw can wait indefinitely. Roll back that new entry on submission failure so later attempts can retry.

Wrap each asynchronous preparation/submission block in a catch-all that removes its just-added variant and rethrows the original exception. Both callers retain shader_mu for the entire operation, so another selector cannot observe the entry before successful submission. If jobs_push returns, ownership remains in the cache for the accepted callback; it is not removed. The queue either inserts successfully or throws before acceptance, and has no throwing operation after insertion. Unwinding destroys temporary captures before the catch removes the Program. Synchronous compute/forced-sync translation and successfully submitted job execution retain their existing behavior.

The regression compiles actual production Program creation, Job metadata/copies, captures, submission and rollback statements. Authored state/code structures and a small queue use real C++ allocation failures. On unchanged main a failed preparation leaves the extra variant and fails the regression. With the fix, 48 cases (44 allocation failures) cover graphics/mesh with optional stages present/absent, preserving an earlier cached variant, retrying every rejected attempt, and executing accepted callbacks to completion. The callback only models readiness, not translation or Vulkan; no game data, driver, real OOM or gameplay stall measurement is involved. The existing real-worker/wait-stealing regression passes too.

Found during #18's lifetime audit; this is a reproduced orphaned-pending-state bug, not proof of the reported gameplay RSS growth. #129 corrects enqueue counters separately and is not required for this cache rollback. Published tree def1c1c3066518ef57659b2c989badb3b7abe816 matches the local staged tree; full local suite finished with 285 passed, the same 12 known host/tool-dependent failure paths, and 56 skipped. Fresh hosted Windows/Linux source/packaging checks are pending. Keep draft until validation completes.