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/skills/requesting-code-review/SKILL.md

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+---
+name: requesting-code-review
+description: Use when completing tasks, implementing major features, or before merging to verify work meets requirements
+---
+
+# Requesting Code Review
+
+Run a structured review pass to catch issues before they cascade.
+
+**Core principle:** Review early, review often.
+
+## When to Request Review
+
+**Mandatory:**
+
+- After each task in single-flow task execution
+- After completing major feature
+- Before merge to main
+
+**Optional but valuable:**
+
+- When stuck (fresh perspective)
+- Before refactoring (baseline check)
+- After fixing complex bug
+
+## How to Request
+
+**1. Get git SHAs:**
+
+```bash
+BASE_SHA=$(git rev-parse HEAD~1)  # or origin/main
+HEAD_SHA=$(git rev-parse HEAD)
+```
+
+**2. Run structured code review checklist:**
+
+Use `requesting-code-review/code-reviewer.md` template and review the diff against requirements. In Antigravity single-flow mode, do not dispatch generic coding agents.
+
+**Placeholders:**
+
+- `{WHAT_WAS_IMPLEMENTED}` - What you just built
+- `{PLAN_OR_REQUIREMENTS}` - What it should do
+- `{BASE_SHA}` - Starting commit
+- `{HEAD_SHA}` - Ending commit
+- `{DESCRIPTION}` - Brief summary
+
+**3. Act on feedback:**
+
+- Fix Critical issues immediately
+- Fix Important issues before proceeding
+- Note Minor issues for later
+- Push back if reviewer is wrong (with reasoning)
+
+## Example
+
+```
+[Just completed Task 2: Add verification function]
+
+You: Let me request code review before proceeding.
+
+BASE_SHA=$(git log --oneline | grep "Task 1" | head -1 | awk '{print $1}')
+HEAD_SHA=$(git rev-parse HEAD)
+
+[Run checklist-based review]
+  WHAT_WAS_IMPLEMENTED: Verification and repair functions for conversation index
+  PLAN_OR_REQUIREMENTS: Task 2 from docs/plans/deployment-plan.md
+  BASE_SHA: a7981ec
+  HEAD_SHA: 3df7661
+  DESCRIPTION: Added verifyIndex() and repairIndex() with 4 issue types
+
+[Review returns]:
+  Strengths: Clean architecture, real tests
+  Issues:
+    Important: Missing progress indicators
+    Minor: Magic number (100) for reporting interval
+  Assessment: Ready to proceed
+
+You: [Fix progress indicators]
+[Continue to Task 3]
+```
+
+## Integration with Workflows
+
+**Single-Flow Task Execution:**
+
+- Review after EACH task
+- Catch issues before they compound
+- Fix before moving to next task
+
+**Executing Plans:**
+
+- Review after each batch (3 tasks)
+- Get feedback, apply, continue
+
+**Ad-Hoc Development:**
+
+- Review before merge
+- Review when stuck
+
+## Red Flags
+
+**Never:**
+
+- Skip review because "it's simple"
+- Ignore Critical issues
+- Proceed with unfixed Important issues
+- Argue with valid technical feedback
+
+**If reviewer wrong:**
+
+- Push back with technical reasoning
+- Show code/tests that prove it works
+- Request clarification
+
+See template at: requesting-code-review/code-reviewer.md