fix: numeric skill names, ultrawork missing run_in_background, ZWSP agent lookups

- #3354: Coerce data.name to String in loadSkillFromPath/loadSkillFromPathAsync
  to prevent crash when YAML parses numeric skill names (e.g., name: 12306)

- #3416: Add required run_in_background parameter to all task() examples in
  ultrawork prompts (default, gpt, gemini, planner) to match tool schema

- #3379/#3417/#3418/#3337/#3335: Strip ZWSP (U+200B) before agent name
  comparisons in agent-tool-restrictions, sync-prompt-sender, tool-execute-after,
  tool-execute-before, oracle-verification-detector, call-omo-agent,
  recovery-prompt-config, and agent-variant to prevent ZWSP-prefixed display
  names from breaking exact-match lookups

src/tools/delegate-task/sync-prompt-sender.ts

@@ -8,6 +8,7 @@ import {
 } from "../../shared/model-suggestion-retry"
 import { formatDetailedError } from "./error-formatting"
 import { getAgentToolRestrictions } from "../../shared/agent-tool-restrictions"
+import { stripInvisibleAgentCharacters } from "../../shared/agent-display-names"
 import { applySessionPromptParams } from "../../shared/session-prompt-params-helpers"
 import { setSessionTools } from "../../shared/session-tools-store"
 import { createInternalAgentTextPart } from "../../shared/internal-initiator-marker"
@@ -41,7 +42,7 @@ function buildPromptGenerationParams(model: DelegatedModelConfig | undefined): R
 }
 
 function isOracleAgent(agentToUse: string): boolean {
-  return agentToUse.toLowerCase() === "oracle"
+  return stripInvisibleAgentCharacters(agentToUse).toLowerCase() === "oracle"
 }
 
 function isUnexpectedEofError(error: unknown): boolean {
@@ -80,7 +81,7 @@ export async function sendSyncPrompt(
   const promptArgs = {
     path: { id: input.sessionID },
     body: {
-      agent: input.agentToUse.replace(/^\u200B+/, ""),
+      agent: stripInvisibleAgentCharacters(input.agentToUse),
       system: input.systemContent,
       tools,
       parts: [createInternalAgentTextPart(effectivePrompt)],