docs pass

docs/RENDER_CADENCE_GOLDEN_RULES.md

@@ -58,6 +58,8 @@ It must not:
 
 If no completed frame is available, record the miss and keep the ownership boundary intact.
 
+DeckLink input is also an edge, not a renderer. It may capture/copy the latest supported CPU frame into an input mailbox and update input telemetry, but it must not call GL, schedule output, compile shaders, or drive render cadence. Format decode that requires GL belongs to the render-owned input upload path.
+
 ## 4. Runtime Build Work Produces Artifacts
 
 Runtime shader work is split into two phases:
@@ -112,6 +114,10 @@ Good examples:
 - `completedPollMisses`
 - `scheduleFailures`
 - `decklinkBuffered`
+- `inputCaptureFps`
+- `inputSubmitMs`
+- `inputUploadMs`
+- `inputConvertMs`
 - `shaderCommitted`
 - `shaderFailures`