Lg1: Implement both light|darkAmbience stimBuffs & their production

We now produce both light and dark ambience stimframes into
stimbuffs for the LivoxGen1 lidar devices.

docs/design/stencils.md

@@ -19,7 +19,8 @@ descriptors tell it exactly which body spots are raising it.
 This direct information also assists SMO in narrowing down the scope of its
 DB searches for methods to handle (increase or decrease) the stimval. For
 example, for a negtrin raised from a `negtrin(...)` segment attached to a
-nontrin DAP line (e.g. `pcloudAmbience`), we don't search DB by trying to
+nontrin DAP line (e.g. `pcloudLightAmbience` / `pcloudDarkAmbience`),
+we don't search DB by trying to
 match all possible body spots with their stimvals. Rather, we search for
 all the body spots that are described in the stencil. This optimizes DB
 searches and also makes negtrin relieving/postrin satisfying searches
@@ -90,15 +91,15 @@ raising new intrins.
 	|livoxProto1()|SERIAL
 ```
 
-The Livox Gen1 **`pcloudAmbience`** sensory line does **not** use
-`n-stencils`; ambience floats are delivered in the stimulus frame buffer.
-If Livox adds `n-stencils` for its intrinsic pipelines, it would appear
-inside the `postrin(...)` / `negtrin(...)` segments attached to
-`pcloudAmbience`, not on `pcloudAmbience` itself.
+The Livox Gen1 **`pcloudLightAmbience`** / **`pcloudDarkAmbience`** sensory
+lines do **not** use `n-stencils`; each emits one `uint32` passband count
+per stimframe. If Livox adds `n-stencils` for its intrinsic pipelines, it
+would appear inside the `postrin(...)` / `negtrin(...)` segments attached to
+the ambience line, not on the ambience qualeIfaceApi itself.
 
 **Invalid (sensory qualeIfaceApi must not carry intrin-oriented params):**
 ```
-+idev|my-device|pcloudAmbience(n-stencils=4)|livoxGen1-pcloud()|livoxProto1()|3JEDK380010Z39
++idev|my-device|pcloudLightAmbience(n-stencils=4)|livoxGen1-pcloud()|livoxProto1()|3JEDK380010Z39
 ```
 
 ## Notes