chore: use American spelling and add agent spelling rule

.claude/CLAUDE.md

@@ -36,3 +36,12 @@ Don't hand-edit a file that has the generated header — the next
 `sdk:generate` run silently overwrites it. Instead, fix the emitter or the
 spec upstream and regenerate. If a requested fix lands in a generated file,
 say so and point at the upstream repo rather than patching it here.
+
+## Spelling
+
+Write American English in hand-maintained code, comments, docs and test names
+(`behavior`, `canceled`, `honor`), per the
+[WorkOS writing style guide](https://app.notion.com/p/workos/Writing-In-Our-Product-6975915fa9a74150916c669d562afe16#5d75728e33a040efa879e598340b8523).
+Never respell a name or value that already ships: public types, methods,
+parameters, API fields and enum values, generated files, and third-party
+commands or identifiers keep their spelling.

src/workos/_base_client.py

@@ -250,7 +250,7 @@ def _query_value(value: Any) -> str:
     def _encode_query(params: Optional[Dict[str, Any]]) -> str:
         """Encode query parameters into a query string.
 
-        Mirrors httpx 0.28 so behaviour is identical for every HTTP backend:
+        Mirrors httpx 0.28 so behavior is identical for every HTTP backend:
         booleans become ``true`` / ``false``, ``None`` becomes an empty value,
         lists and tuples repeat the key, everything else is ``str()``-ed.
         Generated resources rely on this for raw ``bool``, ``int`` and ``list``

src/workos/_http.py

@@ -58,7 +58,7 @@ class HTTPResponse:
 
     ``headers`` must be a case-insensitive mapping (``httpx2.Headers`` and
     ``multidict.CIMultiDictProxy`` both qualify): the SDK reads ``Retry-After``
-    and ``x-request-id`` without normalising case.
+    and ``x-request-id`` without normalizing case.
     """
 
     status_code: int