fix: added README plus minor fixes

Author: gilcu3

crates/foreign-chain-config-tester/README.md

@@ -0,0 +1,49 @@
+# Foreign-chain RPC config tester
+
+A standalone tool that checks the foreign-chain RPC providers in an MPC node
+config, so a misconfiguration (unreachable URL, wrong/expired API key, or a
+provider pointed at the wrong network) is caught before the node hits it in
+production.
+
+For each configured provider it runs a fixed request against a known reference
+transaction — the same inspector and auth handling the node uses — and compares
+the result against a known-good value. Every provider is checked independently:
+one bad provider does not stop the others from being reported.
+
+## Usage
+
+```bash
+cargo run -p foreign-chain-config-tester -- --config /path/to/user-config.toml
+```
+
+`--config` accepts any of the config shapes the project uses, in YAML or TOML
+(format is inferred from the extension):
+
+- the dstack `user-config.toml` (`foreign_chains` under `mpc_node_config.node`);
+- the launcher config (`foreign_chains` under `node`);
+- the legacy `config.yaml` (`foreign_chains` at the top level).
+
+### Network
+
+Reference transactions are network-specific. The network is auto-detected from
+the config (`chain_id`, falling back to `mpc_contract_id`). Override it — or set
+it for configs that carry no such field — with `--network`:
+
+```bash
+cargo run -p foreign-chain-config-tester -- --config user-config.toml --network testnet
+```
+
+## Output
+
+A row per provider, plus a summary line. The process exits non-zero if any
+provider failed.
+
+```
+CHAIN     PROVIDER   RESULT
+abstract  public     ✓ ok
+bitcoin   public     ✓ ok
+starknet  public     ✗ inner network client failed to fetch: Transaction hash not found
+aptos     public     – skipped (no testnet reference transaction for this chain)
+
+3 passed, 1 failed, 1 skipped
+```

crates/foreign-chain-config-tester/src/config.rs

@@ -151,7 +151,7 @@ rpc_url = "https://mainnet.base.org"
 kind = "none"
 "#;
 
-    const RUNTIME_YAML: &str = r#"
+    const LEGACY_YAML: &str = r#"
 my_near_account_id: sam.test.near
 foreign_chains:
   base:
@@ -185,10 +185,10 @@ foreign_chains:
     }
 
     #[test]
-    fn parse_foreign_chains__should_read_top_level_runtime_yaml() {
+    fn parse_foreign_chains__should_read_top_level_legacy_yaml() {
         // Given
         // When
-        let fc = parse_foreign_chains(RUNTIME_YAML, Path::new("config.yaml")).unwrap();
+        let fc = parse_foreign_chains(LEGACY_YAML, Path::new("config.yaml")).unwrap();
 
         // Then
         assert!(fc.base.is_some());

crates/foreign-chain-config-tester/src/main.rs

@@ -31,9 +31,7 @@ use crate::report::{ProviderResult, Status};
 
 /// Verify a node's foreign-chain RPC provider configuration.
 ///
-/// Probes every configured provider with a fixed golden request. Any API-key
-/// environment variables referenced by the config must be set, exactly as when
-/// running the node.
+/// Probes every configured provider with a fixed golden request.
 #[derive(Parser)]
 #[command(about, long_about = None)]
 struct Args {