Add v3 project structure

Author: xiangtinghe616-blip

versions/v3/README.md

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+# Cash Reconciliation Automation v3
+
+v3 is the planned enterprise-readiness upgrade of the cash reconciliation automation project.
+
+The goal is to evolve the current v2 prototype into a more modular, testable, and reviewable reconciliation workflow while keeping the same core design principle:
+
+> deterministic reconciliation logic first, human review for exceptions, and AI only as an assistant layer.
+
+## Planned v3 Direction
+
+v3 will focus on four upgrade areas:
+
+1. **Data contracts and validation**
+   - Add schema checks for bank statement and internal ledger files.
+   - Validate required columns, data types, allowed values, and missing fields before reconciliation.
+
+2. **Modular reconciliation engine**
+   - Refactor standardization, canonicalization, matching, exception classification, and publishing logic into separate modules.
+   - Preserve v2 output behavior through regression tests.
+
+3. **Candidate matching and review workflow**
+   - Keep exact and high-confidence deterministic matching first.
+   - Add a more structured candidate review layer for possible matches and exceptions.
+
+4. **Analyst-facing review interface**
+   - Build toward a dashboard or workbench that allows users to inspect matched transactions, possible matches, exceptions, and data-quality issues.
+
+## Proposed Structure
+
+```text
+versions/v3/
+  schemas/
+  contracts/
+    gx/
+  src/
+    adapters/
+    core/
+    generation/
+    matching/
+    reconciliation/
+    assistant/
+    orchestration/
+    ui/
+  tests/
+  ```
+## Design Principles
+
+- Use synthetic or anonymized demonstration data only.
+- Keep reconciliation decisions auditable and explainable.
+- Treat AI-generated explanations as support, not final decision logic.
+- Separate public presentation assets from code, data, and generated artifacts.
+- Preserve existing v2 behavior before adding new functionality.