Sync camera profiles through the library, and name the tone curves

camera-profiles.md §13: the derived sync pass gains a profiles step,
after the catalog and before the place, that exchanges the profiles
directory with <library>/.darkroom-derived/profiles. Profiles are
immutable and named for what they hold, so name and size decide: it
uploads what the server lacks or holds at another size and downloads
what this device lacks — parsed before it is kept, written beside its
name and renamed — then reloads the set, so a profile copied out of a
DNG on the desktop renders the body's CR2s on the tablet after its
next sync. Like the place it never fails the pass. Not a catalog
table: a schema change would stop an older peer merging at all.

Labels for the view transform's new curve choice: Curve, Camera Raw,
Sigmoid.

ui/dr-ui/src/labels.rs

@@ -227,6 +227,11 @@ fn catalogued(key: &str) -> Option<&'static str> {
         "param.view_transform.contrast" => "Contrast",
         // In stops above middle grey: where the scene reaches display white.
         "param.view_transform.white" => "White Point",
+        // The view transform's curve (D21): Camera Raw's tone, as Lightroom
+        // renders a raw, or D19's sigmoid with its highlight shoulder.
+        "param.view_transform.curve" => "Curve",
+        "param.view_transform.curve.camera_raw" => "Camera Raw",
+        "param.view_transform.curve.sigmoid" => "Sigmoid",
         "param.temperature" => "Temperature",
         "param.tint" => "Tint",
         "param.exposure" => "Exposure",