fix(codex): config.toml compat with codex CLI 0.122+

- model_reasoning_effort: "extra-high" → "xhigh" (the variant name was
  tightened in a recent codex CLI release; "extra-high" now fails config
  load)
- Remove [model_providers.ollama] and [model_providers.lmstudio]
  overrides — codex CLI 0.122+ reserves these as built-in provider IDs
  and rejects overrides. The same localhost endpoints are used by the
  built-ins, so the overrides were redundant anyway. Profiles that
  reference `model_provider = "ollama"` continue to work via the
  built-in.

.codex/config.toml

@@ -2,7 +2,7 @@
 # Shared between CLI and IDE extension
 
 model = "gpt-5.4"
-model_reasoning_effort = "extra-high"
+model_reasoning_effort = "xhigh"
 approval_policy = "on-request"
 sandbox_mode = "workspace-write"
 personality = "pragmatic"
@@ -12,7 +12,7 @@ personality = "pragmatic"
 
 [profiles.review]
 model = "gpt-5.4"
-model_reasoning_effort = "extra-high"
+model_reasoning_effort = "xhigh"
 approval_policy = "never"
 sandbox_mode = "read-only"
 
@@ -47,14 +47,9 @@ FORGE_TOKEN = "${FORGE_TOKEN}"
 CORE_BRAIN_KEY = "${CORE_BRAIN_KEY}"
 MONITOR_INTERVAL = "15s"
 
-# Local model providers
-[model_providers.ollama]
-name = "Ollama"
-base_url = "http://127.0.0.1:11434/v1"
-
-[model_providers.lmstudio]
-name = "LM Studio"
-base_url = "http://127.0.0.1:1234/v1"
+# Model providers: codex CLI 0.122+ ships built-in `ollama` and `lmstudio`
+# providers pointing at the same default localhost ports, so project-level
+# overrides are both redundant and rejected ("reserved built-in provider IDs").
 
 # Agent configuration
 [agents]