feat: API endpoint for LLM call logs by job_id

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/handlers/llm_logs.rs

@@ -0,0 +1,37 @@
+//! Handler for LLM call log viewing.
+
+use axum::extract::{Path, State};
+use axum::response::IntoResponse;
+use axum::Json;
+use uuid::Uuid;
+
+use crate::app_state::AppState;
+use crate::db;
+use crate::errors::AppError;
+use crate::middleware::auth::AuthUser;
+
+/// GET /api/v1/llm-logs/:job_id
+///
+/// Returns all LLM call log entries for a generation job.
+pub async fn get_logs(
+    auth_user: AuthUser,
+    State(state): State<AppState>,
+    Path(job_id): Path<Uuid>,
+) -> Result<impl IntoResponse, AppError> {
+    // Verify the job_id belongs to a synthesis owned by this user
+    let synthesis = sqlx::query_scalar::<_, Uuid>(
+        "SELECT id FROM syntheses WHERE job_id = $1 AND user_id = $2 LIMIT 1",
+    )
+    .bind(job_id)
+    .bind(auth_user.id)
+    .fetch_optional(&state.pool)
+    .await?;
+
+    if synthesis.is_none() {
+        return Err(AppError::NotFound("No synthesis found for this job".into()));
+    }
+
+    let logs = db::llm_call_log::list_by_job_id(&state.pool, auth_user.id, job_id).await?;
+
+    Ok(Json(logs))
+}

backend/src/handlers/mod.rs

@@ -5,6 +5,7 @@ pub mod auth;
 pub mod config;
 pub mod generation;
 pub mod health;
+pub mod llm_logs;
 pub mod settings;
 pub mod sources;
 pub mod syntheses;

backend/src/router.rs

@@ -57,6 +57,8 @@ pub fn build_router(state: AppState, config: &AppConfig) -> Router {
         // Article history & provenance routes (authenticated)
         .route("/article-history", get(handlers::article_history::list_history))
         .route("/syntheses/{id}/provenance", get(handlers::article_history::get_provenance))
+        // LLM call log routes (authenticated)
+        .route("/llm-logs/{job_id}", get(handlers::llm_logs::get_logs))
         // Syntheses CRUD routes (authenticated)
         .route("/syntheses", get(handlers::syntheses::list))
         .route("/syntheses/{id}", get(handlers::syntheses::get))