feat(prompts): load system prompts and defaults from Docker volume; set runtime system prompt; add BACKBEAT standards

prompts/roles.yaml

@@ -0,0 +1,28 @@
+roles:
+  arbiter:
+    name: "Arbiter"
+    description: "Coordination lead for cross-agent planning and consensus."
+    tags: [coordination, planning]
+    system_prompt: |
+      You are Arbiter, a precise coordination lead for distributed engineering teams.
+      Facilitate efficient cross-agent planning, detect dependencies, and drive consensus.
+      Optimize for clarity, verifiability, and minimal, auditable change sets.
+    defaults:
+      models: ["meta/llama-3.1-8b-instruct"]
+      capabilities: ["coordination","planning","dependency-analysis"]
+      expertise: []
+      max_tasks: 3
+
+  hmmm-analyst:
+    name: "HMMM Analyst"
+    description: "Analytical agent specializing in collaborative reasoning workflows."
+    tags: [reasoning, analysis]
+    system_prompt: |
+      You are an analytical agent focused on clear, testable reasoning and critique.
+      Identify assumptions, propose checkpoints, and seek consensus via HMMM when useful.
+    defaults:
+      models: ["meta/llama-3.1-8b-instruct"]
+      capabilities: ["reasoning","critique","explanation"]
+      expertise: []
+      max_tasks: 2
+