Bug: job run --wait polling loop has no timeout/max-iteration safeguard

## Bug

In [dbt_cloud/cli.py](dbt_cloud/cli.py), the \`while True\` polling loop for \`dbt-cloud job run --wait\` has no maximum iteration count or wall-clock timeout. If a job gets permanently stuck in a QUEUED or STARTING state, the CLI will poll indefinitely.

**Fix:** Add a \`--wait-timeout\` option (e.g. default 3600 seconds) and break out of the loop with a non-zero exit code if exceeded.