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/main/assistant/assistant-database.ts

@@ -8742,6 +8742,10 @@ export class AssistantDatabase {
     }
   }
 
+  readStoryGraph(name: import('../../shared/story-graph-tools').StoryGraphToolName, input: unknown, projectId?: string, signal?: AbortSignal): Record<string, unknown> {
+    return readStoryGraph(this.requireDatabase(), name, input, projectId, signal)
+  }
+
   getSupervisionResult(id: string): { id: string; summary: string } | undefined {
     return this.requireDatabase().prepare('SELECT id, summary FROM supervision_results WHERE id = ?').get(id) as { id: string; summary: string } | undefined
   }
@@ -11488,3 +11492,4 @@ export class AssistantDatabase {
 }
 import type { ImageOperation } from '../../shared/image-generation-contracts'
 import { SupervisionReviewStore, supervisionReviewMigration } from './supervision-review-store'
+import { readStoryGraph } from './story-graph-reader'