fix(agents): strip ZWSP ordering prefixes in session state, config lookups, and override protection

Prevent ZWSP sort prefixes from leaking into stored agent names, config
key lookups, and override-protection normalization. Ensures prefixed
list-display names resolve correctly throughout the pipeline.

🤖 Generated with [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode) assistance

src/plugin-handlers/agent-override-protection.ts

@@ -1,7 +1,9 @@
 const PARENTHETICAL_SUFFIX_PATTERN = /\s*(\([^)]*\)\s*)+$/u
+const ZERO_WIDTH_CHARACTERS_PATTERN = /[\u200B\u200C\u200D\uFEFF]/g
 
 export function normalizeProtectedAgentName(agentName: string): string {
   return agentName
+    .replace(ZERO_WIDTH_CHARACTERS_PATTERN, "")
     .trim()
     .toLowerCase()
     .replace(PARENTHETICAL_SUFFIX_PATTERN, "")