perf: optimize SQLite with WAL mode and performance pragmas

Author: cachebag

backend/src/db/mod.rs

@@ -5,6 +5,23 @@ pub async fn create_pool(database_url: &str) -> Result<SqlitePool, sqlx::Error>
         .max_connections(5)
         .connect(database_url)
         .await?;
+    
+    sqlx::query("PRAGMA journal_mode = WAL")
+        .execute(&pool)
+        .await?;
+    
+    sqlx::query("PRAGMA synchronous = NORMAL")
+        .execute(&pool)
+        .await?;
+    
+    sqlx::query("PRAGMA cache_size = -64000")
+        .execute(&pool)
+        .await?;
+    
+    sqlx::query("PRAGMA temp_store = MEMORY")
+        .execute(&pool)
+        .await?;
+    
     Ok(pool)
 }
 

backend/src/main.rs

@@ -26,6 +26,7 @@ use handlers::{
     audit as audit_handlers, auth, budget, export, fixed_expenses, health, income, items, months,
     savings, stats,
 };
+use middleware::audit::audit_middleware;
 use middleware::auth::auth_middleware;
 use middleware::cache::{cache_middleware, CacheState};
 use middleware::ratelimit::{rate_limit_middleware, RateLimitState};
@@ -161,6 +162,10 @@ async fn main() {
         .fallback_service(ServeDir::new("/app/static"))
         .layer(cors)
         .with_state(pool.clone())
+        .layer(axum::middleware::from_fn_with_state(
+            pool.clone(),
+            audit_middleware,
+        ))
         .route_layer(axum::middleware::from_fn_with_state(
             cache_state.clone(),
             cache_middleware,