fix(agent-names): use HTTP-header-safe display names and config keys for API calls (#3138)

Display names with parentheses like 'Atlas (Plan Executor)' cause HTTP
header validation errors in x-opencode-agent-name. This was blocking
Atlas/Prometheus from working via /start-work and auto-retry.

Changes:
- Display names: parens -> dashes ('Atlas - Plan Executor')
- Hooks (start-work, no-hephaestus-non-gpt, no-sisyphus-gpt): use
  config keys ('atlas', 'sisyphus', 'hephaestus') for agent API fields
- auto-retry: use config key instead of display name for promptAsync
- agent-override-protection: handle dash-suffix normalization
- Updated all test expectations to match new format

Closes #3138

src/hooks/start-work/index.test.ts

@@ -453,7 +453,7 @@ You are starting a Sisyphus work session.
       )
 
       // then
-      expect(output.message.agent).toBe(getAgentListDisplayName("atlas"))
+      expect(output.message.agent).toBe("atlas")
     })
 
     test("should switch to Atlas even when current session is Sisyphus (regression: #3155)", async () => {
@@ -473,7 +473,7 @@ You are starting a Sisyphus work session.
       )
 
       // atlas is registered in beforeEach, so it must be selected
-      expect(output.message.agent).toBe(getAgentListDisplayName("atlas"))
+      expect(output.message.agent).toBe("atlas")
       expect(sessionState.getSessionAgent("ses-sisyphus-to-atlas")).toBe("atlas")
     })
 
@@ -496,7 +496,7 @@ You are starting a Sisyphus work session.
       )
 
       // then
-      expect(output.message.agent).toBe("Sisyphus (Ultraworker)")
+      expect(output.message.agent).toBe("sisyphus")
       expect(sessionState.getSessionAgent("ses-prometheus-to-sisyphus")).toBe("sisyphus")
     })
 
@@ -524,7 +524,7 @@ You are starting a Sisyphus work session.
       )
 
       // then
-      expect(output.message.agent).toBe("Sisyphus (Ultraworker)")
+      expect(output.message.agent).toBe("sisyphus")
       expect(sessionState.getSessionAgent("ses-prometheus-to-worker")).toBe("sisyphus")
       expect(readBoulderState(testDir)?.agent).toBe("sisyphus")
     })
@@ -559,7 +559,7 @@ You are starting a Sisyphus work session.
       )
 
       // then
-      expect(output.message.agent).toBe("Sisyphus (Ultraworker)")
+      expect(output.message.agent).toBe("sisyphus")
       expect(readBoulderState(testDir)?.agent).toBe("sisyphus")
     })
 
@@ -594,7 +594,7 @@ You are starting a Sisyphus work session.
       await atlasHook.handler({ event: { type: "session.idle", properties: { sessionID: "session-123" } } })
 
       // then
-      expect(output.message.agent).toBe(getAgentListDisplayName("atlas"))
+      expect(output.message.agent).toBe("atlas")
       expect(readBoulderState(testDir)?.session_ids).toContain("session-123")
       expect(readBoulderState(testDir)?.agent).toBe("atlas")
       expect(promptAsyncMock).toHaveBeenCalledTimes(1)
@@ -684,7 +684,7 @@ You are starting a Sisyphus work session.
         await firePendingTimers()
 
         // then
-        expect(output.message.agent).toBe(getAgentListDisplayName("atlas"))
+        expect(output.message.agent).toBe("atlas")
         expect(readBoulderState(testDir)?.session_ids).toContain("session-123")
         expect(readBoulderState(testDir)?.agent).toBe("atlas")
         expect(promptAsyncMock).toHaveBeenCalledTimes(1)

src/hooks/start-work/start-work-hook.ts

@@ -85,12 +85,12 @@ export function createStartWorkHook(ctx: PluginInput) {
     const activeAgent = isAgentRegistered("atlas")
       ? "atlas"
       : "sisyphus"
-    const activeAgentDisplayName = activeAgent === "atlas"
-      ? getAgentListDisplayName(activeAgent)
-      : getAgentDisplayName(activeAgent)
+    const activeAgentDisplayName = getAgentDisplayName(activeAgent)
     updateSessionAgent(input.sessionID, activeAgent)
     if (output.message) {
-      output.message["agent"] = activeAgentDisplayName
+      // Use config key for agent field to avoid HTTP header validation issues
+      // Display names like "Atlas (Plan Executor)" contain parens that are invalid in headers
+      output.message["agent"] = activeAgent
     }
 
     const existingState = readBoulderState(ctx.directory)