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/lib/changePayload.test.ts

@@ -0,0 +1,97 @@
+import { describe, it, expect } from "vitest";
+import { buildChangePayload, buildChangeSql } from "./changePayload";
+import type { QueueItem } from "../stores/dbViewerStore";
+
+const base = { id: "c1", status: "pending" as const, createdAt: 0 };
+
+describe("buildChangePayload", () => {
+  it("insert -> {schema, table, data}", () => {
+    const item: QueueItem = { ...base, type: "insert", sql: "", schema: "public", table: "t",
+      newData: { a: 1 } } as unknown as QueueItem;
+    const p = buildChangePayload(item);
+    expect(p).toEqual({ id: "c1", type: "insert", schema: "public", table: "t", data: "{\"a\":1}" });
+  });
+
+  it("delete -> {schema, table, primary_key}", () => {
+    const item = { ...base, type: "delete", sql: "", schema: "public", table: "t",
+      primaryKey: { id: 5 } } as unknown as QueueItem;
+    expect(buildChangePayload(item)).toEqual({ id: "c1", type: "delete", schema: "public", table: "t", primary_key: "{\"id\":5}" });
+  });
+
+  it("bulk_insert -> {schema, table, columns, rows}", () => {
+    const item = { ...base, type: "bulk_insert", sql: "", schema: "public", table: "t",
+      columns: ["a", "b"], rows: [[1, 2], [3, 4]] } as unknown as QueueItem;
+    expect(buildChangePayload(item)).toEqual({ id: "c1", type: "bulk_insert", schema: "public", table: "t", columns: ["a", "b"], rows: [[1, 2], [3, 4]] });
+  });
+
+  it("drop_table -> {schema, table}", () => {
+    const item = { ...base, type: "drop_table", sql: "", schema: "public", table: "t" } as unknown as QueueItem;
+    expect(buildChangePayload(item)).toEqual({ id: "c1", type: "drop_table", schema: "public", table: "t" });
+  });
+
+  it("empty_table -> {schema, table}", () => {
+    const item = { ...base, type: "empty_table", sql: "", schema: "public", table: "t" } as unknown as QueueItem;
+    expect(buildChangePayload(item)).toEqual({ id: "c1", type: "empty_table", schema: "public", table: "t" });
+  });
+
+  it("alter_table -> {schema, table, sql, rollback_sql}", () => {
+    const item = { ...base, type: "alter_table", sql: "ALTER TABLE t ADD c int", schema: "public", table: "t" } as unknown as QueueItem;
+    expect(buildChangePayload(item)).toEqual({ id: "c1", type: "alter_table", schema: "public", table: "t", sql: "ALTER TABLE t ADD c int", rollback_sql: "" });
+  });
+});
+
+describe("buildChangeSql", () => {
+  it("insert", () => {
+    const item = { id: "1", type: "insert", schema: "public", table: "t", newData: { a: 1, b: "x" } } as any;
+    expect(buildChangeSql(item)).toBe('INSERT INTO "public"."t" ("a", "b") VALUES (1, \'x\')');
+  });
+  it("update", () => {
+    const item = { id: "1", type: "update", schema: "public", table: "t", primaryKey: { id: 5 }, newData: { name: "O'Brien" } } as any;
+    expect(buildChangeSql(item)).toBe('UPDATE "public"."t" SET "name" = \'O\'\'Brien\' WHERE "id" = 5');
+  });
+  it("delete", () => {
+    const item = { id: "1", type: "delete", schema: "public", table: "t", primaryKey: { id: 5 } } as any;
+    expect(buildChangeSql(item)).toBe('DELETE FROM "public"."t" WHERE "id" = 5');
+  });
+  it("bulk_insert", () => {
+    const item = { id: "1", type: "bulk_insert", schema: "public", table: "t", columns: ["a", "b"], rows: [[1, "y"], [2, null]] } as any;
+    expect(buildChangeSql(item)).toBe('INSERT INTO "public"."t" ("a", "b") VALUES (1, \'y\'), (2, NULL)');
+  });
+  it("empty_table / drop_table", () => {
+    expect(buildChangeSql({ id: "1", type: "empty_table", schema: "public", table: "t" } as any)).toBe('DELETE FROM "public"."t"');
+    expect(buildChangeSql({ id: "1", type: "drop_table", schema: "public", table: "t" } as any)).toBe('DROP TABLE "public"."t"');
+  });
+});
+
+function rebuildItem(sql: string): QueueItem {
+  return {
+    id: "ch-rb1", type: "rebuild_table", sql, status: "pending",
+    createdAt: 0,
+  } as unknown as QueueItem;
+}
+
+describe("rebuild_table payload", () => {
+  it("builds a rebuild_table payload with the script", () => {
+    const p = buildChangePayload(rebuildItem("CREATE TABLE _t();"));
+    expect(p).toEqual({ id: "ch-rb1", type: "rebuild_table", sql: "CREATE TABLE _t();" });
+  });
+  it("buildChangeSql returns the script verbatim", () => {
+    expect(buildChangeSql(rebuildItem("SELECT 1;"))).toBe("SELECT 1;");
+  });
+});
+
+const ddlItem: QueueItem = {
+  id: "ch-1", type: "ddl",
+  sql: "CREATE TYPE public.role AS ENUM ('admin')",
+  status: "pending", createdAt: 0,
+};
+describe("ddl change", () => {
+  it("builds a ddl payload with id + type + sql", () => {
+    expect(buildChangePayload(ddlItem)).toEqual({
+      id: "ch-1", type: "ddl", sql: "CREATE TYPE public.role AS ENUM ('admin')",
+    });
+  });
+  it("preview SQL is the raw sql", () => {
+    expect(buildChangeSql(ddlItem)).toBe("CREATE TYPE public.role AS ENUM ('admin')");
+  });
+});