refactor: resolve critical concurrency, data loss, schema, and search audit passes

server/src/handlers/tasks.rs

@@ -269,7 +269,7 @@ impl McpTool for TasksHandler {
                             let status_match = match req.status.as_deref() {
                                 Some("all") => true,
                                 Some(s) => t.status.eq_ignore_ascii_case(s),
-                                None => t.status != "done" && t.status != "completed",
+                                None => t.is_active(),
                             };
                             let branch_match = match &req.git_branch {
                                 Some(branch) => t.git_branch.is_none() || t.git_branch.as_deref() == Some(branch.as_str()),