Add new skills and utilities for enhanced writing and testing

- Introduced graphviz conventions for visualizing process flows in writing skills.
- Added a comprehensive guide on persuasion principles to improve skill design effectiveness.
- Implemented a script to render graphviz diagrams from markdown files to SVG format.
- Created a detailed reference for testing skills with subagents, emphasizing TDD principles.
- Established a task tracker template for live task management.
- Developed a shell script to check the integrity of the antigravity profile and required files.
- Added test scripts to validate the initialization of agent projects.
- Created workflows for brainstorming, executing plans, and writing plans to streamline processes.

tests/init.test.mjs

@@ -0,0 +1,79 @@
+import { mkdtemp, mkdir, rm, access } from "node:fs/promises";
+import { constants as fsConstants } from "node:fs";
+import { join, resolve } from "node:path";
+import { spawnSync } from "node:child_process";
+import { tmpdir } from "node:os";
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const cliPath = resolve(
+  process.cwd(),
+  "bin/antigravity-superpowers.js",
+);
+
+async function pathExists(path) {
+  try {
+    await access(path, fsConstants.F_OK);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+function runCli(args, cwd) {
+  return spawnSync(process.execPath, [cliPath, ...args], {
+    cwd,
+    encoding: "utf8",
+  });
+}
+
+async function createTempProject(prefix) {
+  const baseTmp = tmpdir();
+  await mkdir(baseTmp, { recursive: true });
+  return mkdtemp(join(baseTmp, prefix));
+}
+
+test("init creates .agent in a fresh project", async () => {
+  const projectDir = await createTempProject("agsp-fresh-");
+
+  try {
+    const result = runCli(["init"], projectDir);
+    assert.equal(result.status, 0);
+
+    const hasAgent = await pathExists(join(projectDir, ".agent", "AGENTS.md"));
+    assert.equal(hasAgent, true);
+  } finally {
+    await rm(projectDir, { recursive: true, force: true });
+  }
+});
+
+test("init fails when .agent exists without --force", async () => {
+  const projectDir = await createTempProject("agsp-existing-");
+
+  try {
+    await mkdir(join(projectDir, ".agent"), { recursive: true });
+
+    const result = runCli(["init"], projectDir);
+    assert.equal(result.status, 1);
+    assert.match(result.stderr, /already exists/i);
+    assert.match(result.stderr, /--force/i);
+  } finally {
+    await rm(projectDir, { recursive: true, force: true });
+  }
+});
+
+test("init replaces .agent with --force", async () => {
+  const projectDir = await createTempProject("agsp-force-");
+
+  try {
+    await mkdir(join(projectDir, ".agent"), { recursive: true });
+
+    const result = runCli(["init", "--force"], projectDir);
+    assert.equal(result.status, 0);
+
+    const hasTemplate = await pathExists(join(projectDir, ".agent", "AGENTS.md"));
+    assert.equal(hasTemplate, true);
+  } finally {
+    await rm(projectDir, { recursive: true, force: true });
+  }
+});