Fix envelope name matching: use word-level instead of substring matching

Prevents false matches where short names are substrings of longer names
(e.g., "Anna" incorrectly matching "Giovanna"). Now every word in the
shorter name must appear as a whole word in the longer name.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/server/src/services/envelopeService.ts

@@ -51,11 +51,19 @@ export function lookupEnvelopeNumber(senderName: string): string | null {
   const exact = cache.get(normalizedSender);
   if (exact) return exact;
 
-  // 2. Check if the sender name is contained in any envelope name or vice versa
+  // 2. Word-level match: every word in the shorter name must appear as a
+  //    whole word in the longer name.  This prevents "Anna" from matching
+  //    "Giovanna" while still allowing "Jean Dupont" to match
+  //    "Jean et Marie Dupont".
   for (const [envName, envNum] of cache) {
-    // Sender "Jean Dupont" matches envelope "Jean et Marie DUPONT"
-    // Sender "Dupont" matches envelope with "DUPONT" in it
-    if (envName.includes(normalizedSender) || normalizedSender.includes(envName)) {
+    const senderWords = normalizedSender.split(' ');
+    const envWords = envName.split(' ');
+    // Pick shorter set as the "query" words and the longer set as the pool
+    const [query, pool] =
+      senderWords.length <= envWords.length
+        ? [senderWords, envWords]
+        : [envWords, senderWords];
+    if (query.length > 0 && query.every(w => pool.includes(w))) {
       return envNum;
     }
   }