GeezerVison

The two SRC_BATCHES_* env vars declared by codingAgent steps
(see sourcegraph/sourcegraph#12503) resolve to different values on
every dequeue. Strip them from cache-key inputs so the key stays
stable across runs.

…p SRC_EXECUTOR_NAME

The per-job env vars declared by codingAgent steps were renamed in
sourcegraph/sourcegraph#12503 (review feedback) from SRC_BATCHES_* to
SRC_EXECUTOR_*, and a third var SRC_EXECUTOR_NAME was added so the
in-sandbox coding-agent CLI can pass X-Sourcegraph-Executor-Name to
the model-provider proxy (lets the server reuse jobAuthMiddleware
instead of a bespoke auth path).

Mirror those changes in src-cli's cache-key stripping list so cached
runs aren't invalidated by the per-dequeue token/ID/executor-name
values that get injected onto step.Env.

One of the three stripped env vars (SRC_EXECUTOR_NAME) is per-executor,
not per-job, so the perJob name is technically wrong. Renaming to
perRunEnvVars accurately captures that all three change on every
dequeue (job-token + job-ID per job, executor-name per executor).