add camera_info input for the pinhole model

Nothing in a dataflow carries fx, fy, cx and cy except the camera, and every
pixel of a depth map needs them to become a 3D point. The node now accepts
them so whatever computes that next has them to hand.

They are read from two places because dora-zed publishes them twice: the
camera_info message, and the metadata of every frame. The per-frame copy is
not redundant -- camera_info goes out once per camera session, so a viewer
started after the camera would otherwise never see it, and reading frame
metadata means wiring the input is optional even for a camera that publishes
it.

A nine-element row-major K is accepted alongside the compact [fx, fy, cx, cy],
since that is how ROS spells the same model in sensor_msgs/CameraInfo.

The model is drawn under the caption rather than only stored. A depth map read
through the wrong intrinsics looks entirely plausible, and this is where that
becomes visible.

as_float32 moves to a payload module: camera_info arrives as a raw byte slice
for the same reason the depth map does, and the reinterpretation is now shared
rather than written twice.

Verified with dora-cli 1.0.1: validate passes with four contracts injected on
each side, the dataflow runs to a clean exit, and a composed frame was
rendered and inspected with the model drawn on it.

dora_image_view/view.py

@@ -5,6 +5,8 @@ from dataclasses import dataclass, field
 import cv2
 import numpy as np
 
+from dora_image_view.intrinsics import Intrinsics
+
 WINDOW = "Dora Node: dora-image-view"
 GREEN = (0, 255, 0)
 WHITE = (255, 255, 255)
@@ -40,6 +42,7 @@ class View:
     bboxes: Bboxes = field(default_factory=Bboxes)
     text: str = ""
     panels: dict[str, np.ndarray] = field(default_factory=dict)
+    intrinsics: Intrinsics | None = None
 
     def show(self) -> bool:
         """Draw the overlays, tile the panels, and display them.
@@ -79,6 +82,13 @@ class View:
         # On the composite, not on a panel: the caption describes the frame as a
         # whole, and a panel it was drawn on might not be the leftmost one.
         cv2.putText(frame, self.text, (20, 20), FONT, FONT_SCALE, WHITE, 1)
+
+        # Showing the camera model is the point of receiving it here: a depth
+        # map read through the wrong intrinsics looks entirely plausible, and
+        # this is where that becomes visible.
+        if self.intrinsics is not None:
+            cv2.putText(frame, str(self.intrinsics), (20, 40), FONT, FONT_SCALE, WHITE, 1)
+
         return frame
 
     def _label(self, panel: np.ndarray, name: str) -> np.ndarray: