Q15: show which messages each agent actually read

Runs record a context manifest once a model turn succeeds; the chat
marks each human message with the agents that read its current version.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main/database/migrations/061-task-run-context.ts

@@ -0,0 +1,6 @@
+export const taskRunContextSchema = `
+  alter table task_runs add column context_json text;
+
+  insert into schema_migrations(version, name, applied_at)
+  values (61, 'task_run_context', datetime('now'));
+`;

src/main/database/schema.ts

@@ -59,6 +59,7 @@ import { kimiCodeProviderSchema } from "./migrations/057-kimi-code-provider";
 import { integrationKeysSchema } from "./migrations/058-integration-keys";
 import { taskHandoffSchema } from "./migrations/059-task-handoff";
 import { chatWakeTextPurgeSchema } from "./migrations/060-chat-wake-text-purge";
+import { taskRunContextSchema } from "./migrations/061-task-run-context";
 
 interface Migration {
   version: number;
@@ -127,6 +128,7 @@ const MIGRATIONS: Migration[] = [
   { version: 58, name: "integration_keys", sql: integrationKeysSchema },
   { version: 59, name: "task_handoff", sql: taskHandoffSchema },
   { version: 60, name: "chat_wake_text_purge", sql: chatWakeTextPurgeSchema },
+  { version: 61, name: "task_run_context", sql: taskRunContextSchema },
 ];
 
 const SCHEMA_VERSION = MIGRATIONS[MIGRATIONS.length - 1].version;