_PROXY_MaxBudgetLimiter re-checked spend:user:{id} against user_max_budget in
async_pre_call_hook without the zero-cost model exemption that
_user_max_budget_check applies in auth, so free models were rejected with
"Max budget limit reached." once a user was over budget. Auth already owns
this check, so the hook is deleted rather than taught the exemption again
Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Several file references under proxy/management_helpers/ and other
paths no longer exist; the code moved to proxy/common_utils/,
proxy/db/db_transaction_queue/, litellm_enterprise/proxy/common_utils/,
proxy/hooks/litellm_skills/, and litellm_core_utils/.
