style: apply rustfmt, fix clippy warnings, and minor code cleanup

Reformat Rust code with rustfmt, suppress clippy::too_many_arguments
for Tauri IPC commands, derive Default for AppSettings, fix unused
variable pattern in TableDataView, and add unit tests for utils.

src-tauri/src/commands/data.rs

@@ -10,6 +10,7 @@ use std::time::Instant;
 use tauri::State;
 
 #[tauri::command]
+#[allow(clippy::too_many_arguments)]
 pub async fn get_table_data(
     state: State<'_, Arc<AppState>>,
     connection_id: String,
@@ -55,7 +56,7 @@ pub async fn get_table_data(
 
     // Always run table data queries in a read-only transaction to prevent
     // writable CTEs or other mutation via the raw filter parameter.
-    let mut tx = (&pool).begin().await.map_err(TuskError::Database)?;
+    let mut tx = pool.begin().await.map_err(TuskError::Database)?;
     sqlx::query("SET TRANSACTION READ ONLY")
         .execute(&mut *tx)
         .await
@@ -129,6 +130,7 @@ pub async fn get_table_data(
 }
 
 #[tauri::command]
+#[allow(clippy::too_many_arguments)]
 pub async fn update_row(
     state: State<'_, Arc<AppState>>,
     connection_id: String,
@@ -244,7 +246,7 @@ pub async fn delete_rows(
     let mut total_affected: u64 = 0;
 
     // Wrap all deletes in a transaction for atomicity
-    let mut tx = (&pool).begin().await.map_err(TuskError::Database)?;
+    let mut tx = pool.begin().await.map_err(TuskError::Database)?;
 
     if pk_columns.is_empty() {
         // Fallback: use ctids for row identification

src-tauri/src/commands/management.rs

@@ -336,10 +336,7 @@ pub async fn alter_role(
         options.push(format!("CONNECTION LIMIT {}", limit));
     }
     if let Some(ref valid_until) = params.valid_until {
-        options.push(format!(
-            "VALID UNTIL '{}'",
-            valid_until.replace('\'', "''")
-        ));
+        options.push(format!("VALID UNTIL '{}'", valid_until.replace('\'', "''")));
     }
 
     if !options.is_empty() {

src-tauri/src/commands/mod.rs

@@ -9,5 +9,5 @@ pub mod management;
 pub mod queries;
 pub mod saved_queries;
 pub mod schema;
-pub mod snapshot;
 pub mod settings;
+pub mod snapshot;

src-tauri/src/commands/queries.rs

@@ -43,20 +43,16 @@ pub fn pg_value_to_json(row: &PgRow, index: usize) -> Value {
         }
         "DATE" => try_get!(chrono::NaiveDate),
         "TIME" => try_get!(chrono::NaiveTime),
-        "BYTEA" => {
-            match row.try_get::<Option<Vec<u8>>, _>(index) {
-                Ok(Some(v)) => return Value::String(format!("\\x{}", hex::encode(&v))),
-                Ok(None) => return Value::Null,
-                Err(_) => {}
-            }
-        }
-        "OID" => {
-            match row.try_get::<Option<i32>, _>(index) {
-                Ok(Some(v)) => return Value::Number(serde_json::Number::from(v)),
-                Ok(None) => return Value::Null,
-                Err(_) => {}
-            }
-        }
+        "BYTEA" => match row.try_get::<Option<Vec<u8>>, _>(index) {
+            Ok(Some(v)) => return Value::String(format!("\\x{}", hex::encode(&v))),
+            Ok(None) => return Value::Null,
+            Err(_) => {}
+        },
+        "OID" => match row.try_get::<Option<i32>, _>(index) {
+            Ok(Some(v)) => return Value::Number(serde_json::Number::from(v)),
+            Ok(None) => return Value::Null,
+            Err(_) => {}
+        },
         "VOID" => return Value::Null,
         // Array types (PG prefixes array type names with underscore)
         "_BOOL" => try_get!(Vec<bool>),
@@ -124,7 +120,11 @@ pub async fn execute_query_core(
 
     let result_rows: Vec<Vec<Value>> = rows
         .iter()
-        .map(|row| (0..columns.len()).map(|i| pg_value_to_json(row, i)).collect())
+        .map(|row| {
+            (0..columns.len())
+                .map(|i| pg_value_to_json(row, i))
+                .collect()
+        })
         .collect();
 
     let row_count = result_rows.len();

src-tauri/src/commands/schema.rs

@@ -28,10 +28,7 @@ pub async fn list_databases(
     Ok(rows.iter().map(|r| r.get::<String, _>(0)).collect())
 }
 
-pub async fn list_schemas_core(
-    state: &AppState,
-    connection_id: &str,
-) -> TuskResult<Vec<String>> {
+pub async fn list_schemas_core(state: &AppState, connection_id: &str) -> TuskResult<Vec<String>> {
     let pool = state.get_pool(connection_id).await?;
 
     let flavor = state.get_flavor(connection_id).await;
@@ -593,11 +590,13 @@ pub async fn get_schema_erd(
     let mut tables_map: HashMap<String, ErdTable> = HashMap::new();
     for row in &col_rows {
         let table_name: String = row.get(0);
-        let entry = tables_map.entry(table_name.clone()).or_insert_with(|| ErdTable {
-            schema: schema.clone(),
-            name: table_name,
-            columns: Vec::new(),
-        });
+        let entry = tables_map
+            .entry(table_name.clone())
+            .or_insert_with(|| ErdTable {
+                schema: schema.clone(),
+                name: table_name,
+                columns: Vec::new(),
+            });
         entry.columns.push(ErdColumn {
             name: row.get(1),
             data_type: row.get(2),