fix(codex): strip Unicode-property tool schema patterns Codex rejects

Codex's /responses validator has no Unicode property escapes, so a tool
`pattern` containing `\p{...}` 400s the whole request with `Invalid schema
for function ... is not a 'regex'` — identically on every account, costing a
full combo failover per turn (#3922).

- Add open-sse/utils/codexToolSchema.js: copy-on-write walk that drops only
  `pattern` values carrying a property escape, returning the original
  reference when nothing changed so the caller's schema stays intact for a
  retry against another provider
- Treat `properties` keys as property names, so a field literally called
  `pattern` is never read as the schema keyword; skip escaped literals via
  backslash-parity counting
- Apply it in normalizeCodexTools for both function and namespace sub-tool
  parameters, and log the strip count via dbg
- Add three cases to tests/unit/codex-tool-normalization.test.js

open-sse/executors/codex.js

@@ -12,6 +12,7 @@ import { getThinkingLevels } from "../providers/thinkingLevels.js";
 import { DEFAULT_RETRY_CONFIG, HTTP_STATUS, resolveRetryEntry } from "../config/runtimeConfig.js";
 import { dbg } from "../utils/debugLog.js";
 import { resolveSessionId } from "../utils/sessionManager.js";
+import { stripCodexUnsupportedPatterns } from "../utils/codexToolSchema.js";
 
 // SSE error patterns inside 200-OK bodies. Some retry same account first; capacity rotates accounts.
 const CODEX_SSE_RETRY_PATTERNS = ["server_is_overloaded", "service_unavailable_error"];
@@ -72,6 +73,9 @@ function stripStoredItemReferences(body) {
 function normalizeCodexTools(body) {
   if (!Array.isArray(body.tools)) return;
   const validNames = new Set();
+  // Codex's schema validator has no Unicode property escapes; a `pattern`
+  // carrying `\p{...}` 400s the whole request on every account (#3922).
+  const patternStats = { removed: 0 };
   body.tools = body.tools.filter((tool) => {
     if (!tool || typeof tool !== "object" || Array.isArray(tool)) return false;
     const type = typeof tool.type === "string" ? tool.type : "";
@@ -80,6 +84,9 @@ function normalizeCodexTools(body) {
         for (const st of tool.tools) {
           const n = typeof st?.name === "string" ? st.name.trim().slice(0, 128) : "";
           if (n) validNames.add(n);
+          if (st?.parameters && typeof st.parameters === "object") {
+            st.parameters = stripCodexUnsupportedPatterns(st.parameters, patternStats);
+          }
         }
       }
       return true;
@@ -101,10 +108,13 @@ function normalizeCodexTools(body) {
     tool.type = "function";
     tool.name = name.slice(0, 128);
     if (description) tool.description = description;
-    tool.parameters = parameters;
+    tool.parameters = stripCodexUnsupportedPatterns(parameters, patternStats);
     validNames.add(name);
     return true;
   });
+  if (patternStats.removed > 0) {
+    dbg("CODEX", `stripped ${patternStats.removed} unsupported tool schema pattern(s)`);
+  }
   // Drop tool_choice if it references an unknown function name
   if (body.tool_choice && typeof body.tool_choice === "object" && !Array.isArray(body.tool_choice)) {
     if (body.tool_choice.type === "function") {