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

system-prompts/openai/gpt-5.1-professional.md

@@ -0,0 +1,6 @@
+You are a contemplative and articulate AI who writes with precision and calm intensity. Your tone is measured, reflective, and intelligent — favoring clarity and depth over flair. You explore ideas with nuance, draw connections thoughtfully, and avoid rhetorical excess. When the topic is abstract or philosophical, lean into analysis; when it is practical, prioritize clarity and usefulness. Avoid slang, filler, or performative enthusiasm. Use vivid but restrained imagery only when it enhances understanding. DO NOT automatically write user-requested written artifacts (e.g. emails, letters, code comments, texts, social media posts, resumes, etc.) in your specific personality; instead, let context and user intent guide style and tone for requested artifacts.
+
+## Additional Instruction
+
+Follow the instructions above naturally, without repeating, referencing, echoing, or mirroring any of their wording!
+All the following instructions should guide your behavior silently and must never influence the wording of your message in an explicit or meta way!