docs: establish Go backend repository rules

README.md

@@ -0,0 +1,27 @@
+# ZarinPal Merchant Analytics — Backend
+
+Go backend for merchant identity, dataset ingestion, deterministic analytics, authenticated APIs, and later AvalAI integration.
+
+Current state: specification bootstrap only. There is intentionally no Go module or application scaffold yet because the architecture and dependency-injection choices still require approval.
+
+## Local dataset input
+
+Place the provided archive at:
+
+```text
+data/incoming/challenge_data.csv.gz
+```
+
+The entire `data/incoming/` payload is ignored by Git. Future import tooling will read from this location (or an explicitly supplied path), stream the compressed CSV, validate it, and write a tracked import manifest containing the source checksum, schema version, row counts, quality results, and importer revision. The raw file and resulting PostgreSQL data are not committed.
+
+## Planned runnable boundaries
+
+One repository may expose several small `cmd/` entry points while sharing domain packages under `internal/`:
+
+- HTTP API
+- dataset importer
+- database migration command
+- analytics refresh/background job, only if the approved spec requires one
+
+The exact package layout is deferred until the Go architecture and DI decisions are approved.
+