refactor(agent-priority): use getAgentListDisplayName for ordering

Update agent priority order handler and tests to use

getAgentListDisplayName for consistent runtime-facing names.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/plugin-handlers/agent-priority-order.ts

@@ -1,4 +1,4 @@
-import { getAgentDisplayName } from "../shared/agent-display-names"
+import { getAgentListDisplayName } from "../shared/agent-display-names"
 
 /**
  * CRITICAL: This is the ONLY source of truth for core agent ordering.
@@ -25,7 +25,7 @@ const CORE_AGENT_ORDER: ReadonlyArray<{
   order: number
 }> = CANONICAL_CORE_AGENT_ORDER.map((configKey, index) => ({
   configKey,
-  displayName: getAgentDisplayName(configKey),
+  displayName: getAgentListDisplayName(configKey),
   order: index + 1,
 }))