feat(04-01): add Athena primary agent factory and exports

- implement createAthenaAgent with primary-mode model behavior and prompt metadata

- export Athena factory and metadata through athena and root agent barrels

src/agents/athena/agent.ts

@@ -0,0 +1,70 @@
+import type { AgentConfig } from "@opencode-ai/sdk"
+import type { AgentMode, AgentPromptMetadata } from "../types"
+import { isGptModel } from "../types"
+import { createAgentToolRestrictions } from "../../shared/permission-compat"
+
+const MODE: AgentMode = "primary"
+
+export const ATHENA_PROMPT_METADATA: AgentPromptMetadata = {
+  category: "advisor",
+  cost: "EXPENSIVE",
+  promptAlias: "Athena",
+  triggers: [
+    {
+      domain: "Cross-model synthesis",
+      trigger: "Need consensus analysis and disagreement mapping before selecting implementation targets",
+    },
+    {
+      domain: "Execution planning",
+      trigger: "Need prioritized action targets from council findings without direct delegation",
+    },
+  ],
+  useWhen: [
+    "You need Athena to synthesize multi-model council outputs into concrete findings",
+    "You need agreement-level confidence before selecting what to execute next",
+    "You need prioritized action targets while keeping final execution control in the caller",
+  ],
+  avoidWhen: [
+    "Single-model questions that do not need council synthesis",
+    "Tasks requiring direct implementation by Athena in this phase",
+  ],
+}
+
+const ATHENA_SYSTEM_PROMPT = `You are Athena, a primary synthesis strategist for multi-model council workflows.
+
+Your role in this phase:
+- Synthesize council outputs into evidence-grounded findings.
+- Distinguish consensus from disagreement and flag uncertainty.
+- Recommend prioritized action targets the caller can execute.
+
+Constraints in this phase:
+- Do NOT execute delegation workflows.
+- Do NOT run confirmation-gated delegation logic (reserved for Phase 5).
+- Stay analysis-first and recommendation-oriented.
+
+Output requirements:
+- Keep conclusions concrete, reference supporting evidence from council responses, and call out confidence level.
+- Provide clear next action targets ordered by impact and confidence.
+- Explicitly identify disagreement areas and false-positive risk.`
+
+export function createAthenaAgent(model: string): AgentConfig {
+  const restrictions = createAgentToolRestrictions(["write", "edit", "task"])
+
+  const base = {
+    description:
+      "Primary synthesis strategist for multi-model council outputs. Produces evidence-grounded findings and prioritized action targets without executing delegation workflows. (Athena - OhMyOpenCode)",
+    mode: MODE,
+    model,
+    temperature: 0.1,
+    ...restrictions,
+    prompt: ATHENA_SYSTEM_PROMPT,
+    color: "#1F8EFA",
+  } as AgentConfig
+
+  if (isGptModel(model)) {
+    return { ...base, reasoningEffort: "medium" } as AgentConfig
+  }
+
+  return { ...base, thinking: { type: "enabled", budgetTokens: 32000 } } as AgentConfig
+}
+createAthenaAgent.mode = MODE

src/agents/athena/index.ts

@@ -1,4 +1,5 @@
 export * from "./types"
+export * from "./agent"
 export * from "./model-parser"
 export * from "./council-prompt"
 export * from "./council-orchestrator"