Initial agent skills setup

Common skills shared across Claude Code, Codex, and Antigravity,
plus per-agent extras. sync.sh deploys to each tool's config path.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sync.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+set -e
+
+SKILLS_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# Claude Code
+mkdir -p ~/.claude
+cat "$SKILLS_DIR/common.md" "$SKILLS_DIR/claude_extra.md" > ~/.claude/CLAUDE.md
+echo "  [ok] ~/.claude/CLAUDE.md"
+
+# Codex + Antigravity (shared ~/.agents/skills)
+SKILL_DIR=~/.agents/skills/my-skills
+mkdir -p "$SKILL_DIR"
+{
+  printf -- "---\nname: my-skills\ndescription: Personal coding skills and conventions\n---\n\n"
+  cat "$SKILLS_DIR/common.md"
+  echo ""
+  cat "$SKILLS_DIR/agents_extra.md"
+} > "$SKILL_DIR/SKILL.md"
+echo "  [ok] $SKILL_DIR/SKILL.md"
+
+echo "synced."