fix: make normalizeSchemaForOpenAI recursive for nested objects

Fixes #111. normalizeSchemaForOpenAI only processed the top-level
object schema, leaving nested objects untouched. OpenAI strict mode
rejects schemas where nested objects have properties not listed in
their required array, causing 400 errors on tools with nested params.

Now recurses into properties, items, and anyOf/oneOf/allOf combinators
(matching the pattern used by enforceStrictSchema in codexShim.ts).
Also adds additionalProperties: false to nested objects in strict mode.

Build verified passing.

src/services/api/openaiShim.ts

@@ -235,20 +235,58 @@ function normalizeSchemaForOpenAI(
   schema: Record<string, unknown>,
   strict = true,
 ): Record<string, unknown> {
-  if (schema.type !== 'object' || !schema.properties) return schema
-  const properties = schema.properties as Record<string, unknown>
-  const existingRequired = Array.isArray(schema.required) ? schema.required as string[] : []
-  // OpenAI strict mode requires every property to be listed in required[].
-  // Gemini rejects schemas where required[] contains keys absent from properties,
-  // so only promote keys that actually exist in properties.
-  if (strict) {
-    const allKeys = Object.keys(properties)
-    const required = Array.from(new Set([...existingRequired, ...allKeys]))
-    return { ...schema, required }
+  if (!schema || typeof schema !== 'object' || Array.isArray(schema)) {
+    return (schema ?? {}) as Record<string, unknown>
   }
-  // For Gemini: keep only existing required keys that are present in properties
-  const required = existingRequired.filter(k => k in properties)
-  return { ...schema, required }
+
+  const record = { ...schema }
+
+  if (record.type === 'object' && record.properties) {
+    const properties = record.properties as Record<string, Record<string, unknown>>
+    const existingRequired = Array.isArray(record.required) ? record.required as string[] : []
+
+    // Recurse into each property
+    const normalizedProps: Record<string, unknown> = {}
+    for (const [key, value] of Object.entries(properties)) {
+      normalizedProps[key] = normalizeSchemaForOpenAI(
+        value as Record<string, unknown>,
+        strict,
+      )
+    }
+    record.properties = normalizedProps
+
+    if (strict) {
+      // OpenAI strict mode requires every property to be listed in required[]
+      const allKeys = Object.keys(normalizedProps)
+      record.required = Array.from(new Set([...existingRequired, ...allKeys]))
+      record.additionalProperties = false
+    } else {
+      // For Gemini: keep only existing required keys that are present in properties
+      record.required = existingRequired.filter(k => k in normalizedProps)
+    }
+  }
+
+  // Recurse into array items
+  if ('items' in record) {
+    if (Array.isArray(record.items)) {
+      record.items = (record.items as unknown[]).map(
+        item => normalizeSchemaForOpenAI(item as Record<string, unknown>, strict),
+      )
+    } else {
+      record.items = normalizeSchemaForOpenAI(record.items as Record<string, unknown>, strict)
+    }
+  }
+
+  // Recurse into combinators
+  for (const key of ['anyOf', 'oneOf', 'allOf'] as const) {
+    if (key in record && Array.isArray(record[key])) {
+      record[key] = (record[key] as unknown[]).map(
+        item => normalizeSchemaForOpenAI(item as Record<string, unknown>, strict),
+      )
+    }
+  }
+
+  return record
 }
 
 function convertTools(