Preroll udpate

shaders/SHADER_CONTRACT.md

@@ -105,6 +105,13 @@ Optional fields:
 
 Parameter objects may also include an optional `description` string. The control UI displays it as one-line helper text with the full text available on hover, so use it for short operational guidance rather than long documentation.
 
+Metadata conventions:
+
+- Keep `name` short, human-facing, and in title case.
+- Keep `category` consistent with existing library groups such as `Color`, `Transform`, `Projection`, `Temporal`, `Scopes & Guides`, `Utility`, `Feedback`, and `Calibration`.
+- Keep `description` to one clear sentence in present tense that explains what the shader does for an operator.
+- Avoid placeholder, joke, or overly implementation-heavy descriptions unless the shader is intentionally a diagnostic or broken example.
+
 Shader-visible identifiers must be valid Slang-style identifiers:
 
 - `entryPoint`
@@ -276,13 +283,15 @@ On the first frame, or after a reset, `sampleFeedback` returns transparent black
 
 Feedback resets when:
 
-- layers are added, removed, or reordered
 - a layer bypass state changes
 - a layer changes shader
+- the layer itself is removed
 - a shader is reloaded or recompiled
 - render dimensions change
 - the app restarts
 
+Ordinary stack add/remove/reorder operations on other layers are intended to preserve feedback state for unchanged feedback-enabled layers.
+
 So feedback should be treated as live runtime state, not durable saved state.
 
 ## Slang Entry Point