feat: openai codex support (#292)

* feat(web): add provider oauth management ui

* feat: add OAuth callback support on port 1455

* feat: enhance reasoning effort options and support for OpenAI Codex OAuth

* feat: update twilight-ai dependency to v0.3.4

* refactor: promote openai-codex to first-class client_type, remove auth_type

Replace the previous openai-responses + metadata auth_type=openai-codex-oauth
combo with a dedicated openai-codex client_type. OAuth requirement is now
determined solely by client_type, eliminating the auth_type concept from the
LLM provider domain entirely.

- Add openai-codex to DB CHECK constraint (migration 0047) with data migration
- Add ClientTypeOpenAICodex constant and dedicated SDK/probe branches
- Remove AuthType from SDKModelConfig, ModelCredentials, TriggerConfig, etc.
- Simplify supportsOAuth to check client_type == openai-codex
- Add conf/providers/codex.yaml preset with Codex catalog models
- Frontend: replace auth_type selector with client_type-driven OAuth UI

---------

Co-authored-by: Acbox <acbox0328@gmail.com>

devenv/docker-compose.yml

@@ -95,6 +95,7 @@ services:
       - /etc/localtime:/etc/localtime:ro
     ports:
       - "${MEMOH_DEV_SERVER_PORT:-18080}:8080"
+      - "${MEMOH_DEV_OAUTH_PORT:-1455}:8080"
     healthcheck:
       test: ["CMD-SHELL", "wget --no-verbose --tries=1 --spider http://127.0.0.1:8080/health || exit 1"]
       interval: 5s