refactor: convert to bun-workspaces monorepo (desktop/ + www/)

- Move the Tauri app (React frontend + Rust backend) into desktop/ via
  git mv — configs unchanged (relative paths: tauri.conf.json, vite.config.ts)
- Root package.json becomes a private bun workspace container with
  orchestration scripts; desktop package renamed gridline-desktop
- Scaffold www/ with Astro 7 + Tailwind v4 (hand-wired vite plugin,
  static output, ready for Dokploy)
- Update release.yml for the new layout: projectPath: desktop,
  desktop/src-tauri resource paths, rust-cache workspace path
- Update README + AGENTS.md structure trees and dev commands
- Verified: vitest (1074), cargo test (354), desktop build, tauri dev
  (window launches), tauri build (dmg + app bundles), Astro build

desktop/src/components/editor/DestructiveQueryDialog.test.tsx

@@ -0,0 +1,40 @@
+import { describe, it, expect, vi } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import { DestructiveQueryDialog } from "./DestructiveQueryDialog";
+
+describe("DestructiveQueryDialog", () => {
+  it("renders warning message with the SQL shown", () => {
+    render(
+      <DestructiveQueryDialog open={true} query="DROP TABLE users" onConfirm={() => {}} onCancel={() => {}} />
+    );
+    expect(screen.getByText(/destructive/i)).toBeInTheDocument();
+    expect(screen.getByText(/DROP TABLE users/)).toBeInTheDocument();
+  });
+
+  it("calls onConfirm when 'Execute' is clicked", () => {
+    const onConfirm = vi.fn();
+    render(
+      <DestructiveQueryDialog open={true} query="DELETE FROM users" onConfirm={onConfirm} onCancel={() => {}} />
+    );
+    fireEvent.click(screen.getByText("Execute"));
+    expect(onConfirm).toHaveBeenCalledTimes(1);
+  });
+
+  it("calls onCancel when 'Cancel' is clicked", () => {
+    const onCancel = vi.fn();
+    render(
+      <DestructiveQueryDialog open={true} query="DROP TABLE users" onConfirm={() => {}} onCancel={onCancel} />
+    );
+    fireEvent.click(screen.getByText("Cancel"));
+    expect(onCancel).toHaveBeenCalledTimes(1);
+  });
+
+  it("truncates long queries in the dialog", () => {
+    const longQuery = "DROP TABLE " + "x".repeat(500);
+    render(
+      <DestructiveQueryDialog open={true} query={longQuery} onConfirm={() => {}} onCancel={() => {}} />
+    );
+    const displayed = screen.getByText(/DROP TABLE/);
+    expect(displayed.textContent!.length).toBeLessThan(longQuery.length + 20);
+  });
+});