feat: add centralized API service layer for frontend

- Create frontend/src/api/mod.rs with centralized HTTP client and error handling
- Implement api::auth module (login, logout, check_auth, get_user)
- Implement api::torrent module (add, action, delete, start, stop, set_label, set_priority)
- Implement api::setup module (get_status, setup)
- Implement api::settings module (set_global_limits)
- Implement api::push module (get_public_key, subscribe)
- Update all components to use api service layer instead of direct gloo_net calls
- Add thiserror dependency for error handling

frontend/src/api/mod.rs

@@ -0,0 +1,243 @@
+use gloo_net::http::Request;
+use shared::{AddTorrentRequest, TorrentActionRequest};
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum ApiError {
+    #[error("Network error")]
+    Network,
+    #[error("Server error: {status}")]
+    Server { status: u16 },
+    #[error("Login failed")]
+    LoginFailed,
+    #[error("Unauthorized")]
+    Unauthorized,
+    #[error("Too many requests")]
+    RateLimited,
+}
+
+fn base_url() -> String {
+    "/api".to_string()
+}
+
+pub mod auth {
+    use super::*;
+
+    #[derive(serde::Serialize)]
+    pub struct LoginRequest {
+        pub username: String,
+        pub password: String,
+        pub remember_me: bool,
+    }
+
+    pub async fn login(
+        username: &str,
+        password: &str,
+        remember_me: bool,
+    ) -> Result<(), ApiError> {
+        let req = LoginRequest {
+            username: username.to_string(),
+            password: password.to_string(),
+            remember_me,
+        };
+        let resp = Request::post(&format!("{}/auth/login", base_url()))
+            .json(&req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+
+        if resp.ok() {
+            Ok(())
+        } else if resp.status() == 429 {
+            Err(ApiError::RateLimited)
+        } else {
+            Err(ApiError::LoginFailed)
+        }
+    }
+
+    pub async fn logout() -> Result<(), ApiError> {
+        Request::post(&format!("{}/auth/logout", base_url()))
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+
+    pub async fn check_auth() -> Result<bool, ApiError> {
+        let resp = Request::get(&format!("{}/auth/check", base_url()))
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(resp.ok())
+    }
+
+    #[derive(serde::Deserialize)]
+    pub struct UserResponse {
+        pub username: String,
+    }
+
+    pub async fn get_user() -> Result<UserResponse, ApiError> {
+        let resp = Request::get(&format!("{}/auth/check", base_url()))
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        let user = resp.json().await.map_err(|_| ApiError::Network)?;
+        Ok(user)
+    }
+}
+
+pub mod setup {
+    use super::*;
+
+    #[derive(serde::Serialize)]
+    pub struct SetupRequest {
+        pub username: String,
+        pub password: String,
+    }
+
+    #[derive(serde::Deserialize)]
+    pub struct SetupStatusResponse {
+        pub completed: bool,
+    }
+
+    pub async fn get_status() -> Result<SetupStatusResponse, ApiError> {
+        let resp = Request::get(&format!("{}/setup/status", base_url()))
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        let status = resp.json().await.map_err(|_| ApiError::Network)?;
+        Ok(status)
+    }
+
+    pub async fn setup(username: &str, password: &str) -> Result<(), ApiError> {
+        let req = SetupRequest {
+            username: username.to_string(),
+            password: password.to_string(),
+        };
+        Request::post(&format!("{}/setup", base_url()))
+            .json(&req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+}
+
+pub mod settings {
+    use super::*;
+    use shared::GlobalLimitRequest;
+
+    pub async fn set_global_limits(req: &GlobalLimitRequest) -> Result<(), ApiError> {
+        Request::post(&format!("{}/settings/global-limits", base_url()))
+            .json(req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+}
+
+pub mod push {
+    use super::*;
+    use crate::store::PushSubscriptionData;
+
+    pub async fn get_public_key() -> Result<String, ApiError> {
+        let resp = Request::get(&format!("{}/push/public-key", base_url()))
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        let key = resp.text().await.map_err(|_| ApiError::Network)?;
+        Ok(key)
+    }
+
+    pub async fn subscribe(req: &PushSubscriptionData) -> Result<(), ApiError> {
+        Request::post(&format!("{}/push/subscribe", base_url()))
+            .json(req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+}
+
+pub mod torrent {
+    use super::*;
+
+    pub async fn add(uri: &str) -> Result<(), ApiError> {
+        let req = AddTorrentRequest {
+            uri: uri.to_string(),
+        };
+        Request::post(&format!("{}/torrents/add", base_url()))
+            .json(&req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+
+    pub async fn action(hash: &str, action: &str) -> Result<(), ApiError> {
+        let req = TorrentActionRequest {
+            hash: hash.to_string(),
+            action: action.to_string(),
+        };
+        Request::post(&format!("{}/torrents/action", base_url()))
+            .json(&req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+
+    pub async fn delete(hash: &str) -> Result<(), ApiError> {
+        action(hash, "delete").await
+    }
+
+    pub async fn delete_with_data(hash: &str) -> Result<(), ApiError> {
+        action(hash, "delete_with_data").await
+    }
+
+    pub async fn start(hash: &str) -> Result<(), ApiError> {
+        action(hash, "start").await
+    }
+
+    pub async fn stop(hash: &str) -> Result<(), ApiError> {
+        action(hash, "stop").await
+    }
+
+    pub async fn set_label(hash: &str, label: &str) -> Result<(), ApiError> {
+        use shared::SetLabelRequest;
+        let req = SetLabelRequest {
+            hash: hash.to_string(),
+            label: label.to_string(),
+        };
+        Request::post(&format!("{}/torrents/set_label", base_url()))
+            .json(&req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+
+    pub async fn set_priority(hash: &str, file_index: u32, priority: u8) -> Result<(), ApiError> {
+        use shared::SetFilePriorityRequest;
+        let req = SetFilePriorityRequest {
+            hash: hash.to_string(),
+            file_index,
+            priority,
+        };
+        Request::post(&format!("{}/torrents/set_priority", base_url()))
+            .json(&req)
+            .map_err(|_| ApiError::Network)?
+            .send()
+            .await
+            .map_err(|_| ApiError::Network)?;
+        Ok(())
+    }
+}