feat(viewer): add recorded point colors and trajectory follow

src/k1link/sessions/plugin_contract.py

@@ -11,9 +11,9 @@ import threading
 from collections.abc import Callable, Mapping
 from dataclasses import dataclass
 from pathlib import Path
-from typing import Protocol
+from typing import Literal, Protocol
 
-from .models import ObservationSessionCandidate
+from .models import ObservationSessionCandidate, ReplayCommand
 
 RecordingProgressPulse = Callable[[], None]
 RecordingExportResult = Mapping[str, object]
@@ -38,6 +38,19 @@ class RecordingExporter(Protocol):
     ) -> RecordingExportResult: ...
 
 
+class RecordedPointColorRenderer(Protocol):
+    def __call__(
+        self,
+        command: ReplayCommand,
+        *,
+        application_id: str,
+        recording_id: str,
+        color_mode: Literal["intensity", "height", "distance", "rgb", "class"],
+        palette: Literal["turbo", "viridis", "plasma", "grayscale", "custom"],
+        custom_color: str,
+    ) -> bytes: ...
+
+
 ObservationArchiveDiscovery = Callable[
     [Path],
     tuple[ObservationSessionCandidate, ...],
@@ -66,3 +79,4 @@ class ObservationRuntimeContribution:
 
     archives: tuple[ObservationArchiveSource, ...]
     recording_exporter: RecordingExporter
+    point_color_renderer: RecordedPointColorRenderer | None = None