cli: add 'rate <passphrase>' subcommand (zxcvbn)

crates/relicario-cli/src/main.rs

@@ -179,6 +179,16 @@ enum Commands {
         #[arg(value_enum)]
         shell: Shell,
     },
+
+    /// Rate a passphrase with zxcvbn — prints score (0-4) and estimated
+    /// guesses. Informational only; does not gate vault operations.
+    ///
+    /// Pass `-` as the argument to read one line from stdin instead, which
+    /// keeps the passphrase out of shell history.
+    Rate {
+        /// Passphrase to score, or `-` to read from stdin.
+        passphrase: String,
+    },
 }
 
 #[derive(Subcommand)]
@@ -375,6 +385,7 @@ fn main() -> Result<()> {
             generate(shell, &mut cmd, "relicario", &mut std::io::stdout());
             Ok(())
         }
+        Commands::Rate { passphrase } => cmd_rate(passphrase),
     }
 }
 
@@ -2180,3 +2191,28 @@ struct ParamsKdf {
     argon2_t: u32,
     argon2_p: u32,
 }
+
+fn cmd_rate(passphrase: String) -> Result<()> {
+    let pw: String = if passphrase == "-" {
+        use std::io::BufRead;
+        let stdin = std::io::stdin();
+        let mut line = String::new();
+        stdin.lock().read_line(&mut line)?;
+        line.trim_end_matches(&['\r', '\n'][..]).to_string()
+    } else {
+        passphrase
+    };
+    let est = relicario_core::generators::rate_passphrase(&pw);
+    let label = match est.score {
+        0 => "very weak",
+        1 => "weak",
+        2 => "fair",
+        3 => "good",
+        4 => "strong",
+        _ => "?",
+    };
+    println!("score:    {}/4  ({})", est.score, label);
+    println!("guesses:  ~10^{:.1}", est.guesses_log10);
+    println!("note:     init requires score ≥ 3 (see `relicario init`)");
+    Ok(())
+}

crates/relicario-cli/tests/smart_inputs.rs

@@ -1,6 +1,7 @@
 mod common;
 
 use assert_cmd::Command;
+use predicates::prelude::PredicateBooleanExt;
 use predicates::str::contains;
 
 #[test]
@@ -103,3 +104,35 @@ fn no_groups_cache_env_var_suppresses_write() {
         "groups.cache should not exist when RELICARIO_NO_GROUPS_CACHE=1"
     );
 }
+
+#[test]
+fn rate_strong_passphrase_prints_score_and_guesses() {
+    Command::cargo_bin("relicario").unwrap()
+        .args(["rate", "correct horse battery staple table cocoa rocket spirit ferment"])
+        .assert()
+        .success()
+        .stdout(contains("score:"))
+        .stdout(contains("guesses:"))
+        .stdout(contains("strong"));
+}
+
+#[test]
+fn rate_weak_passphrase_exits_zero_with_weak_label() {
+    // `rate` is informational — does NOT exit nonzero on weak input.
+    // The hard gate lives at `init` (Plan 2B Task 10).
+    Command::cargo_bin("relicario").unwrap()
+        .args(["rate", "password"])
+        .assert()
+        .success()
+        .stdout(contains("very weak").or(contains("weak")));
+}
+
+#[test]
+fn rate_reads_from_stdin_when_arg_is_dash() {
+    Command::cargo_bin("relicario").unwrap()
+        .args(["rate", "-"])
+        .write_stdin("correcthorsebatterystaple\n")
+        .assert()
+        .success()
+        .stdout(contains("score:"));
+}