dita_v2: VenueTelemetrySnapshot + Zinc venue plane (4th shm partition) + local Rust target dir

Upstream-canonical commit of the ~366 lines that sat uncommitted in the working
tree (surveyed in DITAV2_SOA_SURVEY_20260702). Venue telemetry published at every
venue boundary (submit/cancel/reconcile) over the zinc venue_region; SOA per
UV DITAv2 adjudication 2026-07-03.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

prod/clean_arch/dita_v2/contracts.py

@@ -144,6 +144,54 @@ class VenueOrder:
         return max(0.0, float(self.intended_size) - float(self.filled_size))
 
 
+@dataclass(frozen=True)
+class VenueTelemetrySnapshot:
+    """Shared-memory surface for venue-side call boundaries and state."""
+
+    phase: str = "idle"
+    status: str = "IDLE"
+    venue: str = "bingx"
+    endpoint: str = ""
+    method: str = ""
+    intent_id: str = ""
+    trade_id: str = ""
+    slot_id: int = 0
+    asset: str = ""
+    side: TradeSide = TradeSide.FLAT
+    action: str = ""
+    order_id: str = ""
+    client_order_id: str = ""
+    venue_order_status: str = ""
+    venue_event_kind: str = ""
+    message: str = ""
+    retry_after_ms: int = 0
+    timestamp: Optional[datetime] = None
+    details: Dict[str, Any] = field(default_factory=dict)
+
+    def as_dict(self) -> Dict[str, Any]:
+        return {
+            "phase": self.phase,
+            "status": self.status,
+            "venue": self.venue,
+            "endpoint": self.endpoint,
+            "method": self.method,
+            "intent_id": self.intent_id,
+            "trade_id": self.trade_id,
+            "slot_id": int(self.slot_id or 0),
+            "asset": self.asset,
+            "side": self.side.value if hasattr(self.side, "value") else str(self.side),
+            "action": self.action,
+            "order_id": self.order_id,
+            "client_order_id": self.client_order_id,
+            "venue_order_status": self.venue_order_status,
+            "venue_event_kind": self.venue_event_kind,
+            "message": self.message,
+            "retry_after_ms": int(self.retry_after_ms or 0),
+            "timestamp": self.timestamp.isoformat() if hasattr(self.timestamp, "isoformat") else None,
+            "details": dict(self.details),
+        }
+
+
 @dataclass
 class TradeSlot:
     """A single execution slot managed by the v2 kernel."""