fix: correct locktime threshold, PG stats SUM on TEXT, PG locktime width, and translate Italian error strings

- Bug 1: LOCKTIME_THRESHOLD was 5_000_000 instead of BIP-65 value 500_000_000
- Bug 2: PostgreSQL SUM(our_fees) failed on TEXT column; cast to BIGINT
- Bug 3: PostgreSQL locktime INTEGER (i32) widened to BIGINT (i64) with idempotent ALTER
- Translate 4 Italian error strings in xpub.rs to English

src/bin/bal-pusher.rs

@@ -24,7 +24,8 @@ use reqwest::Client as rClient;
 use std::net::SocketAddr;
 use url::Url;
 
-const LOCKTIME_THRESHOLD: i64 = 5000000;
+// BIP-65: locktime values below this are block heights, at or above are UNIX timestamps.
+const LOCKTIME_THRESHOLD: i64 = 500_000_000;
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 #[derive(Debug, Clone, Serialize, Deserialize)]
 struct MyConfig {