fix(database): close canonical restore review gaps

src-tauri/src/database/dao/providers.rs

@@ -100,6 +100,23 @@ pub(crate) fn validate_provider_storage_json(
     if let Some(source) = meta.pricing_model_source.as_deref() {
         super::proxy::validate_pricing_source(source)?;
     }
+    for (field, value) in [
+        ("limitDailyUsd", meta.limit_daily_usd.as_deref()),
+        ("limitMonthlyUsd", meta.limit_monthly_usd.as_deref()),
+    ] {
+        if let Some(value) = value {
+            let parsed = value.parse::<rust_decimal::Decimal>().map_err(|error| {
+                AppError::InvalidInput(format!(
+                    "invalid provider meta {field} for '{app_type}/{provider_id}': {error}"
+                ))
+            })?;
+            if parsed < rust_decimal::Decimal::ZERO {
+                return Err(AppError::InvalidInput(format!(
+                    "negative provider meta {field} for '{app_type}/{provider_id}'"
+                )));
+            }
+        }
+    }
     Ok(())
 }
 
@@ -495,7 +512,17 @@ impl Database {
                 |row| row.get(0),
             )
             .map_err(|e| AppError::Database(e.to_string()))?;
-        Ok(max.map(|v| (v + 1) as usize).unwrap_or(0))
+        match max {
+            Some(value) => value
+                .checked_add(1)
+                .and_then(|next| usize::try_from(next).ok())
+                .ok_or_else(|| {
+                    AppError::InvalidInput(format!(
+                        "provider sort_index cannot advance past {value}"
+                    ))
+                }),
+            None => Ok(0),
+        }
     }
 
     /// 启动时调用：补齐缺失的官方预设供应商（Claude / Codex / Gemini）。

src-tauri/src/database/dao/settings.rs

@@ -25,9 +25,8 @@ impl Database {
             .map_err(|e| AppError::Database(e.to_string()))?;
 
         if let Some(row) = rows.next().map_err(|e| AppError::Database(e.to_string()))? {
-            Ok(Some(
-                row.get(0).map_err(|e| AppError::Database(e.to_string()))?,
-            ))
+            row.get::<_, Option<String>>(0)
+                .map_err(|e| AppError::Database(e.to_string()))
         } else {
             Ok(None)
         }
@@ -325,3 +324,23 @@ impl Database {
         self.set_setting("log_config", &json)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::database::{lock_conn, Database};
+    use crate::error::AppError;
+
+    #[test]
+    fn null_setting_value_hydrates_as_absent() -> Result<(), crate::error::AppError> {
+        let database = Database::memory()?;
+        {
+            let conn = lock_conn!(database.conn);
+            conn.execute(
+                "INSERT INTO settings (key, value) VALUES ('nullable-setting', NULL)",
+                [],
+            )?;
+        }
+        assert_eq!(database.get_setting("nullable-setting")?, None);
+        Ok(())
+    }
+}