feat: let agents read supervisor story graphs

Expose saved decisions, timelines and source evidence through read-only Story Graph tools across Model, Harness and local/remote OpenCode and Continue. Supervisor enablement and runtime assignments govern discovery and calls; reads do not invoke models or modify stored evidence. Remote use requires matching Desktop and Agent changes.

Make Continue discussion show the complete editable message with a separated destination and shared action layout. Sending uses the visible draft without reattaching removed context.

Validation: existing focused MCP, runtime, controlled Linux Host, discussion component and Electron layout checks plus typechecks; staged diff check passed. Cross-scope fact reuse, historical reconstruction and full package acceptance remain deferred.

Release note: Agents can consult saved supervisor decisions and their sources when continuing work. Continue discussion now lets you review and edit the complete message before sending.

src/agent-daemon/runtime-acp-backend.ts

@@ -1173,7 +1173,7 @@ export class RuntimeAcpBackend {
         }
       }
     }
-    if (preparation.imageTool && (preparation.workMode !== 'execute' || !this.#options.blobSink)) {
+    if (preparation.imageTool && ((preparation.imageTool.description && preparation.workMode !== 'execute') || !this.#options.blobSink)) {
       throw new RuntimeAcpBackendError('Image tools require Execute and a desktop transport', 'identity')
     }
     if (requestedModelBridgePolicy !== undefined) {