fix: make Codex TOML base_url editing section-aware

Rewrite setCodexBaseUrl/extractCodexBaseUrl to understand TOML section
boundaries, ensuring base_url is written into the correct
[model_providers.<name>] section instead of being appended to file end.

- Add section-aware TOML helpers in providerConfigUtils.ts
- Extract shared update_codex_toml_field/remove_codex_toml_base_url_if
  in codex_config.rs, deduplicate proxy.rs TOML editing logic
- Replace scattered inline base_url regexes with extractCodexBaseUrl()
- Add comprehensive tests for both Rust and TypeScript implementations

src-tauri/src/codex_config.rs

@@ -9,6 +9,7 @@ use crate::error::AppError;
 use serde_json::Value;
 use std::fs;
 use std::path::Path;
+use toml_edit::DocumentMut;
 
 /// 获取 Codex 配置目录路径
 pub fn get_codex_config_dir() -> PathBuf {
@@ -135,3 +136,335 @@ pub fn read_and_validate_codex_config_text() -> Result<String, AppError> {
     validate_config_toml(&s)?;
     Ok(s)
 }
+
+/// Update a field in Codex config.toml using toml_edit (syntax-preserving).
+///
+/// Supported fields:
+/// - `"base_url"`: writes to `[model_providers.<current>].base_url` if `model_provider` exists,
+///    otherwise falls back to top-level `base_url`.
+/// - `"model"`: writes to top-level `model` field.
+///
+/// Empty value removes the field.
+pub fn update_codex_toml_field(toml_str: &str, field: &str, value: &str) -> Result<String, String> {
+    let mut doc = toml_str
+        .parse::<DocumentMut>()
+        .map_err(|e| format!("TOML parse error: {e}"))?;
+
+    let trimmed = value.trim();
+
+    match field {
+        "base_url" => {
+            let model_provider = doc
+                .get("model_provider")
+                .and_then(|item| item.as_str())
+                .map(str::to_string);
+
+            if let Some(provider_key) = model_provider {
+                // Ensure [model_providers] table exists
+                if doc.get("model_providers").is_none() {
+                    doc["model_providers"] = toml_edit::table();
+                }
+
+                if let Some(model_providers) = doc["model_providers"].as_table_mut() {
+                    // Ensure [model_providers.<provider_key>] table exists
+                    if !model_providers.contains_key(&provider_key) {
+                        model_providers[&provider_key] = toml_edit::table();
+                    }
+
+                    if let Some(provider_table) = model_providers[&provider_key].as_table_mut() {
+                        if trimmed.is_empty() {
+                            provider_table.remove("base_url");
+                        } else {
+                            provider_table["base_url"] = toml_edit::value(trimmed);
+                        }
+                        return Ok(doc.to_string());
+                    }
+                }
+            }
+
+            // Fallback: no model_provider or structure mismatch → top-level base_url
+            if trimmed.is_empty() {
+                doc.as_table_mut().remove("base_url");
+            } else {
+                doc["base_url"] = toml_edit::value(trimmed);
+            }
+        }
+        "model" => {
+            if trimmed.is_empty() {
+                doc.as_table_mut().remove("model");
+            } else {
+                doc["model"] = toml_edit::value(trimmed);
+            }
+        }
+        _ => return Err(format!("unsupported field: {field}")),
+    }
+
+    Ok(doc.to_string())
+}
+
+/// Remove `base_url` from the active model_provider section only if it matches `predicate`.
+/// Also removes top-level `base_url` if it matches.
+/// Used by proxy cleanup to strip local proxy URLs without touching user-configured URLs.
+pub fn remove_codex_toml_base_url_if(toml_str: &str, predicate: impl Fn(&str) -> bool) -> String {
+    let mut doc = match toml_str.parse::<DocumentMut>() {
+        Ok(doc) => doc,
+        Err(_) => return toml_str.to_string(),
+    };
+
+    let model_provider = doc
+        .get("model_provider")
+        .and_then(|item| item.as_str())
+        .map(str::to_string);
+
+    if let Some(provider_key) = model_provider {
+        if let Some(model_providers) = doc
+            .get_mut("model_providers")
+            .and_then(|v| v.as_table_mut())
+        {
+            if let Some(provider_table) = model_providers
+                .get_mut(provider_key.as_str())
+                .and_then(|v| v.as_table_mut())
+            {
+                let should_remove = provider_table
+                    .get("base_url")
+                    .and_then(|item| item.as_str())
+                    .map(&predicate)
+                    .unwrap_or(false);
+                if should_remove {
+                    provider_table.remove("base_url");
+                }
+            }
+        }
+    }
+
+    // Fallback: also clean up top-level base_url if it matches
+    let should_remove_root = doc
+        .get("base_url")
+        .and_then(|item| item.as_str())
+        .map(&predicate)
+        .unwrap_or(false);
+    if should_remove_root {
+        doc.as_table_mut().remove("base_url");
+    }
+
+    doc.to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn base_url_writes_into_correct_model_provider_section() {
+        let input = r#"model_provider = "any"
+model = "gpt-5.1-codex"
+
+[model_providers.any]
+name = "any"
+wire_api = "responses"
+"#;
+
+        let result = update_codex_toml_field(input, "base_url", "https://example.com/v1").unwrap();
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        let base_url = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("any"))
+            .and_then(|v| v.get("base_url"))
+            .and_then(|v| v.as_str())
+            .expect("base_url should be in model_providers.any");
+        assert_eq!(base_url, "https://example.com/v1");
+
+        // Should NOT have top-level base_url
+        assert!(parsed.get("base_url").is_none());
+
+        // wire_api preserved
+        let wire_api = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("any"))
+            .and_then(|v| v.get("wire_api"))
+            .and_then(|v| v.as_str());
+        assert_eq!(wire_api, Some("responses"));
+    }
+
+    #[test]
+    fn base_url_creates_section_when_missing() {
+        let input = r#"model_provider = "custom"
+model = "gpt-4"
+"#;
+
+        let result = update_codex_toml_field(input, "base_url", "https://custom.api/v1").unwrap();
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        let base_url = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("custom"))
+            .and_then(|v| v.get("base_url"))
+            .and_then(|v| v.as_str())
+            .expect("should create section and set base_url");
+        assert_eq!(base_url, "https://custom.api/v1");
+    }
+
+    #[test]
+    fn base_url_falls_back_to_top_level_without_model_provider() {
+        let input = r#"model = "gpt-4"
+"#;
+
+        let result = update_codex_toml_field(input, "base_url", "https://fallback.api/v1").unwrap();
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        let base_url = parsed
+            .get("base_url")
+            .and_then(|v| v.as_str())
+            .expect("should set top-level base_url");
+        assert_eq!(base_url, "https://fallback.api/v1");
+    }
+
+    #[test]
+    fn clearing_base_url_removes_only_from_correct_section() {
+        let input = r#"model_provider = "any"
+
+[model_providers.any]
+name = "any"
+base_url = "https://old.api/v1"
+wire_api = "responses"
+
+[mcp_servers.context7]
+command = "npx"
+"#;
+
+        let result = update_codex_toml_field(input, "base_url", "").unwrap();
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        // base_url removed from model_providers.any
+        let any_section = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("any"))
+            .expect("model_providers.any should exist");
+        assert!(any_section.get("base_url").is_none());
+
+        // wire_api preserved
+        assert_eq!(
+            any_section.get("wire_api").and_then(|v| v.as_str()),
+            Some("responses")
+        );
+
+        // mcp_servers untouched
+        assert!(parsed.get("mcp_servers").is_some());
+    }
+
+    #[test]
+    fn model_field_operates_on_top_level() {
+        let input = r#"model_provider = "any"
+model = "gpt-4"
+
+[model_providers.any]
+name = "any"
+"#;
+
+        let result = update_codex_toml_field(input, "model", "gpt-5").unwrap();
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+        assert_eq!(parsed.get("model").and_then(|v| v.as_str()), Some("gpt-5"));
+
+        // Clear model
+        let result2 = update_codex_toml_field(&result, "model", "").unwrap();
+        let parsed2: toml::Value = toml::from_str(&result2).unwrap();
+        assert!(parsed2.get("model").is_none());
+    }
+
+    #[test]
+    fn preserves_comments_and_whitespace() {
+        let input = r#"# My Codex config
+model_provider = "any"
+model = "gpt-4"
+
+# Provider section
+[model_providers.any]
+name = "any"
+base_url = "https://old.api/v1"
+"#;
+
+        let result = update_codex_toml_field(input, "base_url", "https://new.api/v1").unwrap();
+
+        // Comments should be preserved
+        assert!(result.contains("# My Codex config"));
+        assert!(result.contains("# Provider section"));
+    }
+
+    #[test]
+    fn does_not_misplace_when_profiles_section_follows() {
+        let input = r#"model_provider = "any"
+
+[model_providers.any]
+name = "any"
+base_url = "https://old.api/v1"
+
+[profiles.default]
+model = "gpt-4"
+"#;
+
+        let result = update_codex_toml_field(input, "base_url", "https://new.api/v1").unwrap();
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        // base_url in correct section
+        let base_url = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("any"))
+            .and_then(|v| v.get("base_url"))
+            .and_then(|v| v.as_str());
+        assert_eq!(base_url, Some("https://new.api/v1"));
+
+        // profiles section untouched
+        let profile_model = parsed
+            .get("profiles")
+            .and_then(|v| v.get("default"))
+            .and_then(|v| v.get("model"))
+            .and_then(|v| v.as_str());
+        assert_eq!(profile_model, Some("gpt-4"));
+    }
+
+    #[test]
+    fn remove_base_url_if_predicate() {
+        let input = r#"model_provider = "any"
+
+[model_providers.any]
+name = "any"
+base_url = "http://127.0.0.1:5000/v1"
+wire_api = "responses"
+"#;
+
+        let result =
+            remove_codex_toml_base_url_if(input, |url| url.starts_with("http://127.0.0.1"));
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        let any_section = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("any"))
+            .unwrap();
+        assert!(any_section.get("base_url").is_none());
+        assert_eq!(
+            any_section.get("wire_api").and_then(|v| v.as_str()),
+            Some("responses")
+        );
+    }
+
+    #[test]
+    fn remove_base_url_if_keeps_non_matching() {
+        let input = r#"model_provider = "any"
+
+[model_providers.any]
+base_url = "https://production.api/v1"
+"#;
+
+        let result =
+            remove_codex_toml_base_url_if(input, |url| url.starts_with("http://127.0.0.1"));
+        let parsed: toml::Value = toml::from_str(&result).unwrap();
+
+        let base_url = parsed
+            .get("model_providers")
+            .and_then(|v| v.get("any"))
+            .and_then(|v| v.get("base_url"))
+            .and_then(|v| v.as_str());
+        assert_eq!(base_url, Some("https://production.api/v1"));
+    }
+}