review: a key split by an invisible character is still a secret

has_secret masked each character a character rule matches to a space, so one
zero-width space inside a key cut it into two runs too short to match. The
secret rules now also run on the text with those characters deleted, and the
text is a secret if either matches.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

crates/memoryd/src/honcho/decide.rs

@@ -78,21 +78,24 @@ pub fn peer_name(speaker: &str) -> String {
 
 /// Whether `text` holds a known-prefix secret, by `refuse`'s secret rules alone. `refuse` gives
 /// only the first rule a text breaks, and its character rules come first, so each character they
-/// match is first replaced by a space: it is not a key character and not a letter, so a secret's
-/// prefix and run are found as before, and a carriage return cannot hide a key.
+/// match is taken out of the way, in two ways, and the text is a secret if either is: replaced by
+/// a space, which is not a key character and not a letter, so a secret's prefix and run are found
+/// as before and a carriage return cannot hide a key; and deleted, so that one inside a key cannot
+/// split it into two runs too short to match.
 pub fn has_secret(text: &str) -> bool {
     let mut buf = [0u8; 4];
-    let masked: String = text
-        .chars()
-        .map(|c| {
-            if refuse(c.encode_utf8(&mut buf)).is_some() {
-                ' '
-            } else {
-                c
-            }
-        })
-        .collect();
-    refuse(&masked).is_some_and(|r| r.rule.starts_with("secret-"))
+    let mut masked = String::with_capacity(text.len());
+    let mut deleted = String::with_capacity(text.len());
+    for c in text.chars() {
+        if refuse(c.encode_utf8(&mut buf)).is_some() {
+            masked.push(' ');
+        } else {
+            masked.push(c);
+            deleted.push(c);
+        }
+    }
+    let secret = |t: &str| refuse(t).is_some_and(|r| r.rule.starts_with("secret-"));
+    secret(&masked) || secret(&deleted)
 }
 
 /// The turn's user text and its speaker, from its first record, the `User` one.