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.

scripts/check-pack.mjs

@@ -0,0 +1,53 @@
+import { execFileSync } from "node:child_process";
+import { rm } from "node:fs/promises";
+import { resolve } from "node:path";
+
+const raw = execFileSync("npm", ["pack", "--json"], {
+  cwd: process.cwd(),
+  encoding: "utf8",
+});
+const packResult = JSON.parse(raw);
+
+if (!Array.isArray(packResult) || packResult.length === 0) {
+  throw new Error("npm pack did not return package metadata");
+}
+
+const [{ filename, files }] = packResult;
+if (!filename || !Array.isArray(files)) {
+  throw new Error("npm pack output is missing filename or files");
+}
+
+const packagedPaths = new Set(files.map((file) => file.path));
+const required = [
+  "bin/antigravity-superpowers.js",
+  "src/cli.js",
+  "src/commands/init.js",
+  "templates/.agent/AGENTS.md",
+  "templates/.agent/INSTALL.md",
+  "templates/.agent/task.md",
+  "templates/.agent/workflows/brainstorm.md",
+  "templates/.agent/workflows/write-plan.md",
+  "templates/.agent/workflows/execute-plan.md",
+  "templates/.agent/agents/code-reviewer.md",
+  "templates/.agent/tests/run-tests.sh",
+  "templates/.agent/tests/check-antigravity-profile.sh",
+  "templates/.agent/skills/single-flow-task-execution/SKILL.md",
+  "templates/.agent/skills/single-flow-task-execution/implementer-prompt.md",
+  "templates/.agent/skills/single-flow-task-execution/spec-reviewer-prompt.md",
+  "templates/.agent/skills/single-flow-task-execution/code-quality-reviewer-prompt.md",
+  "templates/.agent/skills/executing-plans/SKILL.md",
+  "templates/.agent/skills/verification-before-completion/SKILL.md",
+  "templates/.agent/skills/writing-plans/SKILL.md",
+  "templates/.agent/skills/test-driven-development/SKILL.md",
+];
+
+const missing = required.filter((path) => !packagedPaths.has(path));
+if (missing.length > 0) {
+  throw new Error(
+    `Packaged tarball is missing required files: ${missing.join(", ")}`,
+  );
+}
+
+await rm(resolve(process.cwd(), filename), { force: true });
+
+process.stdout.write("Pack smoke check passed.\n");