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/tests/run-tests.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+
+echo "========================================"
+echo " Antigravity Profile Test Runner"
+echo "========================================"
+echo ""
+
+bash "$SCRIPT_DIR/check-antigravity-profile.sh"