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.

templates/.agent/INSTALL.md

@@ -0,0 +1,64 @@
+# Install Antigravity Superpowers Profile
+
+This package is a standalone Antigravity profile. It does not modify the original Superpowers source workflows.
+
+## Prerequisites
+
+- Antigravity environment installed
+- Shell access
+- This repository available locally
+
+## Install
+
+From your project root:
+
+```bash
+npx antigravity-superpowers init
+```
+
+Or manually:
+
+```bash
+mkdir -p .agent
+cp -R /path/to/antigravity-superpowers-cli/templates/.agent/* .agent/
+```
+
+If your project already has `.agent/skills`, merge carefully and keep the versions you want.
+
+## What Gets Installed
+
+- `.agent/AGENTS.md`
+- `.agent/task.md` (template only)
+- `.agent/skills/*`
+- `.agent/workflows/*`
+- `.agent/agents/*`
+- `.agent/tests/*`
+
+Runtime tracking file:
+
+- `docs/plans/task.md` in the target project root (created at runtime by skill flow, list-only table)
+
+## Verify Profile
+
+From your target project root:
+
+```bash
+bash .agent/tests/run-tests.sh
+```
+
+Expected result: all checks pass with zero failures.
+
+## Usage Notes
+
+- This profile uses strict single-flow task execution.
+- Generic coding subagents are intentionally not used.
+- Browser automation can use `browser_subagent` when needed.
+- Skill references are local to `.agent/skills`.
+
+## Update
+
+Re-run the CLI init with `--force` to update, then rerun validation:
+
+```bash
+bash .agent/tests/run-tests.sh
+```