fix(rust/receiving-icp): rename staging→ic, drop production environment (#1425)

Aligns with the icp-cli convention used in basic_ethereum:
- staging → ic (standard environment name for ICP mainnet deployments)
- production removed; a comment in icp.yaml explains how to adapt
  ICP_LEDGER_CANISTER_ID for the real ICP ledger

README updated: table now shows ic instead of staging/production, deploy
command is icp deploy -e ic, production guidance points to icp.yaml comment.

Author: marc0olo

rust/receiving-icp/README.md

@@ -11,10 +11,11 @@ The ICP ledger canister ID is configured via `icp.yaml` and read at runtime as a
 | Environment | Ledger | Canister ID |
 |---|---|---|
 | `local` | ICP ledger (pre-deployed by icp-cli) | `ryjl3-tyaaa-aaaaa-aaaba-cai` |
-| `staging` | TESTICP ledger | `xafvr-biaaa-aaaai-aql5q-cai` |
-| `production` | ICP ledger (mainnet) | `ryjl3-tyaaa-aaaaa-aaaba-cai` |
+| `ic` | TESTICP ledger | `xafvr-biaaa-aaaai-aql5q-cai` |
 
-The local environment uses the same principal as production because icp-cli's local network pre-deploys the ICP ledger at that well-known address. Staging uses the TESTICP ledger so you can test token flows without spending real ICP.
+The local environment uses the same canister ID as the mainnet ICP ledger because icp-cli's local network pre-deploys it at that well-known address. The `ic` environment uses the TESTICP ledger so you can test token flows on ICP mainnet without spending real ICP.
+
+For a production deployment using the real ICP ledger, update `ICP_LEDGER_CANISTER_ID` in `icp.yaml` to `ryjl3-tyaaa-aaaaa-aaaba-cai` — see the comment in `icp.yaml` for the exact change.
 
 ## Build and deploy from the command line
 
@@ -41,16 +42,14 @@ icp network stop
 
 `bash test.sh` runs 7 tests: account identifier format, subaccount uniqueness, funding the main account and a specific subaccount via account ID hex, balance queries, and subaccount independence. Tests are delta-based and idempotent across re-runs.
 
-### Deploy to staging or production
+### Deploy to ICP mainnet
 
 ```bash
-# Staging — targets the TESTICP ledger
-icp deploy --environment staging
-
-# Production — targets the mainnet ICP ledger
-icp deploy --environment production
+icp deploy -e ic
 ```
 
+This targets the TESTICP ledger by default. To use the real ICP ledger, update `ICP_LEDGER_CANISTER_ID` in `icp.yaml` first.
+
 ## Security considerations and best practices
 
 Refer to the [security best practices](https://docs.internetcomputer.org/guides/security/overview) for information on security and best practices for your ICP app.

rust/receiving-icp/icp.yaml

@@ -3,28 +3,25 @@ canisters:
     recipe:
       type: "@dfinity/rust@v3.3.0"
 
-# ICP_LEDGER_CANISTER_ID is injected at deploy time by the recipe and baked
-# into the WASM. Deploy with `--environment staging` to target the TESTICP
-# ledger, or omit the flag to use the production ICP ledger (default for
-# both local and production).
+# ICP_LEDGER_CANISTER_ID is injected at deploy time and read at runtime via
+# ic_cdk::api::env_var_value("ICP_LEDGER_CANISTER_ID").
 environments:
+  # Local: icp-cli pre-deploys the ICP ledger at the well-known mainnet address.
   - name: local
     network: local
     settings:
       backend:
         environment_variables:
           ICP_LEDGER_CANISTER_ID: "ryjl3-tyaaa-aaaaa-aaaba-cai"
 
-  - name: staging
+  # IC mainnet: uses the TESTICP ledger by default so you can test token flows
+  # without spending real ICP.
+  #
+  # For a production deployment using the real ICP ledger, change
+  # ICP_LEDGER_CANISTER_ID to "ryjl3-tyaaa-aaaaa-aaaba-cai".
+  - name: ic
     network: ic
     settings:
       backend:
         environment_variables:
           ICP_LEDGER_CANISTER_ID: "xafvr-biaaa-aaaai-aql5q-cai"
-
-  - name: production
-    network: ic
-    settings:
-      backend:
-        environment_variables:
-          ICP_LEDGER_CANISTER_ID: "ryjl3-tyaaa-aaaaa-aaaba-cai"