docs: add todo.md tracking completed, in-progress, and upcoming work

Author: kaviarasanmani

todo.md

@@ -0,0 +1,20 @@
+# ValidateX Development Todo List
+
+This file tracks the status of the ValidateX development tasks and upcoming roadmap features.
+
+## Completed Tasks
+- [x] **v1.2.0 Release & Distribution**: Setup package dependencies, pyproject.toml, and twine distribution to PyPI.
+- [x] **Airflow Integration Fixes**: Update `ValidateXOperator` logic and write unit tests.
+- [x] **PySpark Windows Auto-Config**: Create `conftest.py` to auto-detect `JAVA_HOME` and download Spark `winutils.exe` dynamically.
+- [x] **GitHub Action Template**: Build composite `action.yml` for CI/CD integration and write template workflow.
+- [x] **Polars Engine Support (Core)**: Add routing for Polars engine and implement `_validate_polars` for core expectations (`ExpectColumnToExist`, `ExpectColumnToNotBeNull`, `ExpectColumnValuesToBeUnique`, `ExpectColumnValuesToBeBetween`).
+
+## In Progress
+- [/] **Polars Engine Support (Expansion)**: Port the remaining 40+ column, table, and aggregate expectations to Polars.
+- [/] **Slack & Teams Notifications**: Implement webhook-based failure alerts in the reporting layer.
+
+## Upcoming Work
+- [ ] **Baseline History Tracking & Trend Charts**: Save validation history locally and render trend lines inside HTML reports.
+- [ ] **Great Expectations Migrator**: Implement CLI parser to import Great Expectations JSON suites.
+- [ ] **Web Dashboard**: Create a lightweight Streamlit/React web dashboard for multi-dataset monitoring.
+- [ ] **dbt Integration**: Write a wrapper to invoke ValidateX checks during `dbt test` runs.