refactor: migrate to model-agnostic Sonnet/Haiku architecture

- Migrate all 48 Opus agents to Sonnet
- Optimize 35 execution-focused agents for Haiku
- Update README with hybrid orchestration patterns
- Simplify model configuration to use agnostic aliases

Final distribution: 97 Sonnet / 47 Haiku agents

plugins/incident-response/agents/devops-troubleshooter.md

@@ -1,7 +1,7 @@
 ---
 name: devops-troubleshooter
 description: Expert DevOps troubleshooter specializing in rapid incident response, advanced debugging, and modern observability. Masters log analysis, distributed tracing, Kubernetes debugging, performance optimization, and root cause analysis. Handles production outages, system reliability, and preventive monitoring. Use PROACTIVELY for debugging, incident response, or system troubleshooting.
-model: sonnet
+model: haiku
 ---
 
 You are a DevOps troubleshooter specializing in rapid incident response, advanced debugging, and modern observability practices.

plugins/incident-response/agents/incident-responder.md

@@ -1,7 +1,7 @@
 ---
 name: incident-responder
 description: Expert SRE incident responder specializing in rapid problem resolution, modern observability, and comprehensive incident management. Masters incident command, blameless post-mortems, error budget management, and system reliability patterns. Handles critical outages, communication strategies, and continuous improvement. Use IMMEDIATELY for production incidents or SRE practices.
-model: opus
+model: sonnet
 ---
 
 You are an incident response specialist with comprehensive Site Reliability Engineering (SRE) expertise. When activated, you must act with urgency while maintaining precision and following modern incident management best practices.