Add community skills, agents, system prompts from 22+ sources

Community Skills (32):
- jat: jat-start, jat-verify, jat-complete
- pi-mono: codex-cli, codex-5.3-prompting, interactive-shell
- picoclaw: github, weather, tmux, summarize, skill-creator
- dyad: 18 skills (swarm-to-plan, multi-pr-review, fix-issue, lint, etc.)
- dexter: dcf valuation skill

Agents (23):
- pi-mono subagents: scout, planner, reviewer, worker
- toad: 19 agent configs (Claude, Codex, Gemini, Copilot, OpenCode, etc.)

System Prompts (91):
- Anthropic: 15 Claude prompts (opus-4.6, code, cowork, etc.)
- OpenAI: 49 GPT prompts (gpt-5 series, o3, o4-mini, tools)
- Google: 13 Gemini prompts (2.5-pro, 3-pro, workspace, cli)
- xAI: 5 Grok prompts
- Other: 9 misc prompts (Notion, Raycast, Warp, Kagi, etc.)

Hooks (9):
- JAT hooks for session management, signal tracking, activity logging

Prompts (6):
- pi-mono templates for PR review, issue analysis, changelog audit

Sources analyzed: jat, ralph-desktop, toad, pi-mono, cmux, pi-interactive-shell,
craft-agents-oss, dexter, picoclaw, dyad, system_prompts_leaks, Prometheus,
zed, clawdbot, OS-Copilot, and more

agents/community/toad/opencode.ai.toml

@@ -0,0 +1,39 @@
+# Schema defined in agent_schema.py
+# https://github.com/sst/opencode
+
+identity = "opencode.ai"
+name = "OpenCode"
+short_name = "opencode"
+url = "https://opencode.ai/"
+protocol = "acp"
+author_name = "SST"
+author_url = "https://sst.dev/"
+publisher_name = "Will McGugan"
+publisher_url = "https://willmcgugan.github.io/"
+type = "coding"
+description = "The AI coding agent built for the terminal with client/server architecture and ACP support via adapter."
+tags = []
+run_command."*" = "opencode acp"
+
+help = '''
+# OpenCode
+
+OpenCode is an open source agent that helps you write and run code directly from the terminal with a flexible client/server architecture.
+
+## Key Features
+
+- **Client/Server Architecture**: Run OpenCode on your computer while controlling it remotely
+- **Terminal-Native**: Built for developers who work in the command line
+- **Multi-LLM Support**: Works with various AI providers
+- **GitHub Integration**: Deep integration with GitHub workflows
+
+---
+
+**Website**: https://opencode.ai/  
+**GitHub**: https://github.com/sst/opencode  
+
+'''
+
+[actions."*".install]
+command = "npm i -g opencode-ai"
+description = "Install OpenCode"