Promote AgentCompany-New to the repository root and retire the old app

The legacy application - its src, tests, landing site, promo assets, docs,
release tooling, CI workflows, and root configs - leaves the tree; it stays
reachable in history. Everything under AgentCompany-New moves up unchanged:
same package name, so the production userData/database path is untouched,
and e2e/build scripts already resolved paths relative to the project. The
developer cred.txt stays gitignored at its new location. Full verify:ci
passes from the new root.

src/main/database/connection.ts

@@ -0,0 +1,32 @@
+import { mkdirSync } from "node:fs";
+import { dirname } from "node:path";
+import { DatabaseSync } from "node:sqlite";
+import { installSchema } from "./schema";
+
+export class DatabaseConnection {
+  readonly db: DatabaseSync;
+
+  constructor(dbPath: string) {
+    mkdirSync(dirname(dbPath), { recursive: true });
+    this.db = new DatabaseSync(dbPath);
+    this.db.exec("pragma journal_mode = WAL");
+    this.db.exec("pragma foreign_keys = ON");
+    installSchema(this.db);
+  }
+
+  transaction<T>(operation: () => T): T {
+    this.db.exec("begin immediate");
+    try {
+      const result = operation();
+      this.db.exec("commit");
+      return result;
+    } catch (error) {
+      this.db.exec("rollback");
+      throw error;
+    }
+  }
+
+  close(): void {
+    this.db.close();
+  }
+}