[FIX] Drop Copy session (prediction + perps) #425

Scope

FIX Drop Copy (DC) session for both products — request/response retrieval of historical execution reports, plus the listener-streaming variant.

Messages

• EventResendRequest (U1), EventResendComplete (U2), EventResendReject (U3); inbound ExecutionReport (35=8) replay.
• Custom tags: BeginExecID (21001), EndExecID (21002), ResendEventCount (21003), EventResendRejectReason (21004).

Work

• DC session wiring on the KalshiDC session type (port 8229), request/response query API.
• Listener-streaming support: the deferred logon options ListenerSession (20126) + SkipPendingExecReports (21011) plumbed through FixConfig/session logon.
• Typed inbound execution-report delivery (reuses the OE ExecutionReport model).

Acceptance

State tests for the resend request/complete/reject cycle and listener streaming against the mock acceptor; golden fixtures for U1/U2/U3. ruff + mypy --strict clean.

Dependencies

Foundation #422; Order Entry (ExecutionReport model). Part of #402.