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.

README.md

@@ -0,0 +1,48 @@
+# antigravity-superpowers
+
+CLI for initializing the Antigravity Superpowers profile in any project.
+
+## What `init` does
+
+- Copies bundled profile files into `<project-root>/.agent`
+- Fails safely if `.agent` already exists
+- Supports `--force` to replace existing `.agent`
+
+The CLI does **not** create `docs/plans/task.md`. That live tracker is created at runtime by skill flow.
+
+## Usage
+
+```bash
+antigravity-superpowers init
+```
+
+```bash
+antigravity-superpowers init /path/to/project
+```
+
+```bash
+antigravity-superpowers init --force
+```
+
+## Local Development
+
+From the package directory:
+
+```bash
+npm test
+npm run smoke:pack
+```
+
+## Publish Workflow
+
+The release flow is manual by design.
+
+```bash
+npm version patch
+npm publish
+```
+
+`prepublishOnly` automatically runs:
+
+1. `npm test`
+2. `npm run smoke:pack`