feat(companion): add typed canvas RPC helpers for runtime clients

src/companion/runtimeClient.ts

@@ -185,6 +185,56 @@ export interface SetNodeLocationInput extends Omit<NodeLocationSetParams, 'conne
 
 export interface SetNodePushTokenInput extends Omit<NodePushTokenSetParams, 'connectionId'> {}
 
+export interface CanvasArtifact {
+  id: string;
+  type: string;
+  title?: string;
+  content: unknown;
+  metadata?: Record<string, unknown>;
+  createdAt: number;
+  updatedAt: number;
+}
+
+export interface PutCanvasArtifactInput {
+  sessionId: string;
+  artifactId?: string;
+  type: string;
+  title?: string;
+  content: unknown;
+  metadata?: Record<string, unknown>;
+}
+
+export interface GetCanvasArtifactInput {
+  sessionId: string;
+  artifactId: string;
+}
+
+export interface DeleteCanvasArtifactInput {
+  sessionId: string;
+  artifactId: string;
+}
+
+export interface CanvasPutResult {
+  artifact: CanvasArtifact;
+  upserted: boolean;
+}
+
+export interface CanvasGetResult {
+  artifact: CanvasArtifact;
+}
+
+export interface CanvasListResult {
+  artifacts: CanvasArtifact[];
+}
+
+export interface CanvasDeleteResult {
+  deleted: boolean;
+}
+
+export interface CanvasClearResult {
+  cleared: number;
+}
+
 export class GatewayRpcError extends Error {
   readonly code: number;
 
@@ -378,6 +428,39 @@ export class CompanionRuntimeClient {
     });
   }
 
+  putCanvasArtifact(input: PutCanvasArtifactInput): Promise<CanvasPutResult> {
+    return this.call<CanvasPutResult>('canvas.put', {
+      sessionId: input.sessionId,
+      artifactId: input.artifactId,
+      type: input.type,
+      title: input.title,
+      content: input.content,
+      metadata: input.metadata,
+    });
+  }
+
+  getCanvasArtifact(input: GetCanvasArtifactInput): Promise<CanvasGetResult> {
+    return this.call<CanvasGetResult>('canvas.get', {
+      sessionId: input.sessionId,
+      artifactId: input.artifactId,
+    });
+  }
+
+  listCanvasArtifacts(sessionId: string): Promise<CanvasListResult> {
+    return this.call<CanvasListResult>('canvas.list', { sessionId });
+  }
+
+  deleteCanvasArtifact(input: DeleteCanvasArtifactInput): Promise<CanvasDeleteResult> {
+    return this.call<CanvasDeleteResult>('canvas.delete', {
+      sessionId: input.sessionId,
+      artifactId: input.artifactId,
+    });
+  }
+
+  clearCanvasArtifacts(sessionId: string): Promise<CanvasClearResult> {
+    return this.call<CanvasClearResult>('canvas.clear', { sessionId });
+  }
+
   private handleMessage(raw: string): void {
     let parsed: RpcMessage;
     try {