feat(01-02): add athena to agent name contracts

- add athena to built-in and overridable agent name schemas

- extend BuiltinAgentName with athena for config-level recognition

- make builtin agent source maps partial until athena runtime registration lands

src/agents/builtin-agents.ts

@@ -29,7 +29,7 @@ import { buildCustomAgentMetadata, parseRegisteredAgentSummaries } from "./custo
 
 type AgentSource = AgentFactory | AgentConfig
 
-const agentSources: Record<BuiltinAgentName, AgentSource> = {
+const agentSources: Partial<Record<BuiltinAgentName, AgentSource>> = {
   sisyphus: createSisyphusAgent,
   hephaestus: createHephaestusAgent,
   oracle: createOracleAgent,

src/agents/builtin-agents/general-agents.ts

@@ -10,7 +10,7 @@ import { applyEnvironmentContext } from "./environment-context"
 import { applyModelResolution } from "./model-resolution"
 
 export function collectPendingBuiltinAgents(input: {
-  agentSources: Record<BuiltinAgentName, import("../agent-builder").AgentSource>
+  agentSources: Partial<Record<BuiltinAgentName, import("../agent-builder").AgentSource>>
   agentMetadata: Partial<Record<BuiltinAgentName, AgentPromptMetadata>>
   disabledAgents: string[]
   agentOverrides: AgentOverrides

src/agents/types.ts

@@ -103,6 +103,7 @@ export type BuiltinAgentName =
   | "metis"
   | "momus"
   | "atlas"
+  | "athena"
 
 export type OverridableAgentName =
   | "build"

src/config/schema/agent-names.ts

@@ -11,6 +11,7 @@ export const BuiltinAgentNameSchema = z.enum([
   "metis",
   "momus",
   "atlas",
+  "athena",
 ])
 
 export const BuiltinSkillNameSchema = z.enum([
@@ -36,6 +37,7 @@ export const OverridableAgentNameSchema = z.enum([
   "explore",
   "multimodal-looker",
   "atlas",
+  "athena",
 ])
 
 export const AgentNameSchema = BuiltinAgentNameSchema