fix(athena): address 6 council review findings — launcher, schema, filtering, presentation

- Forward temperature and permission through council-launcher to background manager
- Add LaunchInput.temperature and LaunchInput.permission to background-agent types
- Extract session guard with 5-minute timeout to prevent stale council locks
- Make council optional in AthenaOverrideConfigSchema for partial user overrides
- Support member lookup by both name and model ID in filterCouncilMembers
- Add provider/model-id format validation to CouncilMemberSchema
- Fix findings-presenter group header to show finding count instead of first finding's reporter count

src/config/schema.test.ts

@@ -625,7 +625,7 @@ describe("Athena agent override", () => {
       expect(result.data.agents?.athena?.model).toBe("openai/gpt-5.3-codex")
       expect(result.data.agents?.athena?.temperature).toBe(0.2)
       expect(result.data.agents?.athena?.prompt_append).toBe("Use consensus-first synthesis.")
-      expect(result.data.agents?.athena?.council.members).toHaveLength(3)
+      expect(result.data.agents?.athena?.council?.members).toHaveLength(3)
     }
   })
 
@@ -648,7 +648,7 @@ describe("Athena agent override", () => {
     expect(result.success).toBe(false)
   })
 
-  test("rejects athena override when council is missing", () => {
+  test("accepts athena override without council (temperature-only override)", () => {
     // given
     const config = {
       agents: {
@@ -662,7 +662,7 @@ describe("Athena agent override", () => {
     const result = OhMyOpenCodeConfigSchema.safeParse(config)
 
     // then
-    expect(result.success).toBe(false)
+    expect(result.success).toBe(true)
   })
 })