initial: pi config — agents, prompts, skills, settings

Captures:
- 12 agent definitions (vigilio + a-team + utility)
- 8 mission prompt configurations
- 3 skills (forgejo, senior-software-engineer, xai-docs)
- pi settings.json (default provider/model)

.pi/agent/prompts/implement-and-review.md

@@ -0,0 +1,10 @@
+---
+description: Worker implements, reviewer reviews, worker applies feedback
+---
+Use the subagent tool with the chain parameter to execute this workflow:
+
+1. First, use the "worker" agent to implement: $@
+2. Then, use the "reviewer" agent to review the implementation from the previous step (use {previous} placeholder)
+3. Finally, use the "worker" agent to apply the feedback from the review (use {previous} placeholder)
+
+Execute this as a chain, passing output between steps via {previous}.