chore(core): Debug derive on StrengthEstimate + fix stale test comment

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/idfoto-core/src/generators.rs

@@ -106,6 +106,7 @@ fn bip39_passphrase(word_count: u32, separator: &str, cap: Capitalization) -> Re
 }
 
 /// Returns zxcvbn's 0-4 score (higher is stronger) and the estimated guesses.
+#[derive(Debug, Clone, Copy)]
 pub struct StrengthEstimate {
     pub score: u8,
     pub guesses_log10: f64,
@@ -181,7 +182,7 @@ mod bip39_tests {
 
     #[test]
     fn rate_passphrase_strong_one_passes_gate() {
-        // 5-word bip39 passphrase
+        // 6-word bip39 passphrase
         let req = GeneratorRequest::Bip39 {
             word_count: 6,
             separator: " ".into(),