feat: implement accounting API (accounts, ledger, payments, audit)

.env.example

@@ -0,0 +1,15 @@
+# The application reads configuration from real environment variables (it does
+# NOT load this file at runtime). This file documents them and is read by the
+# sqlx compile-time macros / sqlx-cli at build time (which look up DATABASE_URL).
+# For local runs, export these (e.g. `set -a; . ./.env; set +a`) or pass them in.
+
+# Connection string used by the sqlx macros and sqlx-cli at build time.
+DATABASE_URL=postgres://postgres:postgres@localhost:5432/accounting
+# Connection string read by the application at runtime (see src/main.rs).
+POSTGRESQL_ADDON_URI=postgres://postgres:postgres@localhost:5432/accounting
+
+# Server bind address (optional; defaults shown).
+HOST=0.0.0.0
+PORT=3000
+
+RUST_LOG=info,accounting_api=debug