fix(api): provider endpoint mismatches preventing Copilot save, test, and remove

Fix #415

Three endpoint mismatches between frontend and backend caused the
GitHub Copilot provider's save, test, and remove buttons to fail
with 405 Method Not Allowed. These affected all providers for save.

- change update_provider annotation from post to put to match frontend
- fix test button URL from /providers/test to /providers/test-model
- add github-copilot entry in build_test_llm_config since
  default_provider_config returns None for providers that require
  token exchange
- widen GITHUB_COPILOT_DEFAULT_BASE_URL visibility to pub(crate)
- add unit test for build_test_llm_config with github-copilot

fix(api): Copilot provider shows as available after remove when env var is set

get_providers fell back to the GITHUB_COPILOT_API_KEY env var when the
TOML key was absent, so the provider stayed visible in settings after
a remove — the env var can't be unset from a running process.

Only check the TOML key for Copilot status in the config-exists path.
The env var fallback remains for the no-config-file case (fresh install).

Author: ibhagwan

src/api/providers.rs

@@ -207,6 +207,23 @@ fn build_test_llm_config(provider: &str, credential: &str) -> crate::config::Llm
     let mut providers = HashMap::new();
     if let Some(provider_config) = crate::config::default_provider_config(provider, credential) {
         providers.insert(provider.to_string(), provider_config);
+    } else if provider == "github-copilot" {
+        // GitHub Copilot uses token exchange, so default_provider_config returns None.
+        // For testing, add a provider entry with the PAT as the api_key —
+        // LlmManager::get_copilot_token() will exchange it for a real Copilot token.
+        providers.insert(
+            provider.to_string(),
+            crate::config::ProviderConfig {
+                api_type: crate::config::ApiType::OpenAiChatCompletions,
+                base_url: crate::config::GITHUB_COPILOT_DEFAULT_BASE_URL.to_string(),
+                api_key: credential.to_string(),
+                name: Some("GitHub Copilot".to_string()),
+                use_bearer_auth: true,
+                extra_headers: vec![],
+                api_version: None,
+                deployment: None,
+            },
+        );
     }
 
     crate::config::LlmConfig {
@@ -447,6 +464,15 @@ pub(super) async fn get_providers(
             env_set(env_var)
         };
 
+        // Copilot: only check TOML key, not env var. The env var GITHUB_COPILOT_API_KEY
+        // is a fallback for config loading but shouldn't keep the provider visible in
+        // the settings UI after a remove — the env var can't be unset from the process.
+        let copilot_configured = doc
+            .get("llm")
+            .and_then(|llm| llm.get("github_copilot_key"))
+            .and_then(|val| val.as_str())
+            .is_some_and(|s| resolve_value(s).is_some());
+
         (
             has_value("anthropic_key", "ANTHROPIC_API_KEY"),
             has_value("openai_key", "OPENAI_API_KEY"),
@@ -470,7 +496,7 @@ pub(super) async fn get_providers(
             has_value("minimax_cn_key", "MINIMAX_CN_API_KEY"),
             has_value("moonshot_key", "MOONSHOT_API_KEY"),
             has_value("zai_coding_plan_key", "ZAI_CODING_PLAN_API_KEY"),
-            has_value("github_copilot_key", "GITHUB_COPILOT_API_KEY"),
+            copilot_configured,
             doc.get("llm")
                 .and_then(|llm| llm.get("provider"))
                 .and_then(|provider| provider.get("azure"))
@@ -1607,4 +1633,24 @@ mod tests {
         assert_eq!(provider.base_url, "http://remote-ollama.local:11434");
         assert_eq!(provider.api_key, "");
     }
+
+    #[test]
+    fn build_test_llm_config_registers_github_copilot_provider() {
+        let config = build_test_llm_config("github-copilot", "ghp_test_pat_token");
+        let provider = config
+            .providers
+            .get("github-copilot")
+            .expect("github-copilot provider should be registered");
+
+        assert_eq!(
+            provider.base_url,
+            crate::config::GITHUB_COPILOT_DEFAULT_BASE_URL
+        );
+        assert_eq!(provider.api_key, "ghp_test_pat_token");
+        assert!(provider.use_bearer_auth);
+        assert_eq!(
+            config.github_copilot_key.as_deref(),
+            Some("ghp_test_pat_token")
+        );
+    }
 }

src/config.rs

@@ -18,6 +18,7 @@ pub use permissions::{
     DiscordPermissions, MattermostPermissions, SignalPermissions, SlackPermissions,
     TelegramPermissions, TwitchPermissions,
 };
+pub(crate) use providers::GITHUB_COPILOT_DEFAULT_BASE_URL;
 pub(crate) use providers::default_provider_config;
 pub use runtime::RuntimeConfig;
 pub use types::*;

src/config/providers.rs

@@ -26,7 +26,7 @@ pub(super) const NVIDIA_PROVIDER_BASE_URL: &str = "https://integrate.api.nvidia.
 pub(super) const FIREWORKS_PROVIDER_BASE_URL: &str = "https://api.fireworks.ai/inference";
 pub(crate) const GEMINI_PROVIDER_BASE_URL: &str =
     "https://generativelanguage.googleapis.com/v1beta/openai";
-pub(super) const GITHUB_COPILOT_DEFAULT_BASE_URL: &str = "https://api.individual.githubcopilot.com";
+pub(crate) const GITHUB_COPILOT_DEFAULT_BASE_URL: &str = "https://api.individual.githubcopilot.com";
 
 /// App attribution headers sent with every OpenRouter API request.
 /// See <https://openrouter.ai/docs/app-attribution>.