MCP middleware was discarding tenant_id and api_key_id after authentication.
The authenticate_mcp() call mutated a RequestContext with these fields, but
tools later created a fresh RequestContext without them. This caused
UsageMeteringValidator to see tenant_id="unknown" and skip billing entirely.
Propagate tenant_id and api_key_id via ContextVars (same pattern as bank_id
and api_key) so the RequestContext passed to the memory engine has the full
auth context needed for usage tracking.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
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