docs(architecture): fix stale error-mapping location claim

errors.md and client.md said the httpx2-exception-mapping table
"lives at the terminal in client.py" — true before this branch, but
the body-cap extraction moved the last mapping code out of client.py
entirely, into _internal/exception_mapping.py. Distinguish where the
table lives from where it fires.

Author: lesnik512

architecture/client.md

@@ -4,7 +4,7 @@
 
 ## The internal terminal
 
-The bottom of the middleware chain (the "terminal") is internal. It calls `self._httpx2_client.send(request)`, maps `httpx2` errors to `httpware` errors, and raises a `StatusError` subclass on 4xx/5xx. The error-mapping table (what `httpx2` exception maps to which `httpware` exception) lives at the terminal in `src/httpware/client.py`; status-keyed exceptions are looked up via the `STATUS_TO_EXCEPTION` table in `src/httpware/errors.py`. The same terminal lifecycle holds in both worlds: `Client.send` / `AsyncClient.send` enter the middleware chain first, and it is the internal terminal — `Client._terminal` / `AsyncClient._terminal` — that calls `httpx2.Client.send` / `httpx2.AsyncClient.send`.
+The bottom of the middleware chain (the "terminal") is internal. It calls `self._httpx2_client.send(request)`, maps `httpx2` errors to `httpware` errors, and raises a `StatusError` subclass on 4xx/5xx. The error-mapping table (what `httpx2` exception maps to which `httpware` exception) lives in `src/httpware/_internal/exception_mapping.py` and fires at the terminal in `src/httpware/client.py`; status-keyed exceptions are looked up via the `STATUS_TO_EXCEPTION` table in `src/httpware/errors.py`. The same terminal lifecycle holds in both worlds: `Client.send` / `AsyncClient.send` enter the middleware chain first, and it is the internal terminal — `Client._terminal` / `AsyncClient._terminal` — that calls `httpx2.Client.send` / `httpx2.AsyncClient.send`.
 
 ## Sync/async parity
 

architecture/errors.md

@@ -10,7 +10,7 @@ exc.response.request.url               # URL of the failed request
 
 `__repr__` and the `str()` summary redact URL userinfo (`user:pass@`) and mask the values of known-sensitive query and fragment parameters (e.g. `token`, `api_key`, `secret`) to avoid leaking credentials in tracebacks.
 
-The error-mapping table (what `httpx2` exception maps to which `httpware` exception) lives at the terminal in `src/httpware/client.py`. Status-keyed exceptions are looked up via the `STATUS_TO_EXCEPTION` table in `src/httpware/errors.py`. Unknown 4xx falls back to `ClientStatusError`; unknown 5xx falls back to `ServerStatusError`.
+The error-mapping table (what `httpx2` exception maps to which `httpware` exception) lives in `src/httpware/_internal/exception_mapping.py` and fires at the terminal in `src/httpware/client.py`. Status-keyed exceptions are looked up via the `STATUS_TO_EXCEPTION` table in `src/httpware/errors.py`. Unknown 4xx falls back to `ClientStatusError`; unknown 5xx falls back to `ServerStatusError`.
 
 `TimeoutError` inherits from both `httpware.ClientError` and `builtins.TimeoutError` so `except builtins.TimeoutError` (the form `asyncio.wait_for` uses) also catches httpware-raised timeouts.