add GetCustomColours rpc method

proto/anki/collection.proto

@@ -20,6 +20,7 @@ service CollectionService {
   rpc LatestProgress(generic.Empty) returns (Progress);
   rpc SetWantsAbort(generic.Empty) returns (generic.Empty);
   rpc SetLoadBalancerEnabled(generic.Bool) returns (OpChanges);
+  rpc GetCustomColours(generic.Empty) returns (GetCustomColoursResponse);
 }
 
 // Implicitly includes any of the above methods that are not listed in the
@@ -163,3 +164,7 @@ message CreateBackupRequest {
   bool force = 2;
   bool wait_for_completion = 3;
 }
+
+message GetCustomColoursResponse {
+  repeated string colours = 1;
+}

qt/aqt/mediasrv.py

@@ -630,6 +630,7 @@ post_handler_list = [
 exposed_backend_list = [
     # CollectionService
     "latest_progress",
+    "get_custom_colours",
     # DeckService
     "get_deck_names",
     # I18nService

rslib/src/collection/service.rs

@@ -1,8 +1,10 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+use anki_proto::collection::GetCustomColoursResponse;
 use anki_proto::generic;
 
 use crate::collection::Collection;
+use crate::config::ConfigKey;
 use crate::error;
 use crate::prelude::BoolKey;
 use crate::prelude::Op;
@@ -62,4 +64,13 @@ impl crate::services::CollectionService for Collection {
         })
         .map(Into::into)
     }
+
+    fn get_custom_colours(
+        &mut self,
+    ) -> error::Result<anki_proto::collection::GetCustomColoursResponse> {
+        let colours = self
+            .get_config_optional(ConfigKey::CustomColorPickerPalette)
+            .unwrap_or_default();
+        Ok(GetCustomColoursResponse { colours })
+    }
 }

rslib/src/config/mod.rs

@@ -71,6 +71,7 @@ pub(crate) enum ConfigKey {
     NextNewCardPosition,
     #[strum(to_string = "schedVer")]
     SchedulerVersion,
+    CustomColorPickerPalette,
 }
 
 #[derive(PartialEq, Eq, Serialize_repr, Deserialize_repr, Clone, Copy, Debug)]