feat(person): add name-match tokenizer for direct matching (#763)

Lowercase, split on whitespace/hyphen/apostrophe, drop empties. Applied
symmetrically to query and candidate name components so "Anna-Maria" and
"Anna Maria" tokenize alike. Foundation for resolveByName direct matching.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/test/java/org/raddatz/familienarchiv/person/PersonServiceTest.java

@@ -909,4 +909,36 @@ class PersonServiceTest {
         assertThat(result).containsExactly(walter);
         verify(personRepository).searchByName("Walter");
     }
+
+    // ─── tokenize (name-match contract) ───────────────────────────────────────
+
+    @Test
+    void tokenize_hyphenatedName_splitsOnHyphen() {
+        assertThat(PersonService.tokenize("Anna-Maria")).containsExactly("anna", "maria");
+    }
+
+    @Test
+    void tokenize_apostropheName_splitsOnApostrophe() {
+        assertThat(PersonService.tokenize("D'Angelo")).containsExactly("d", "angelo");
+    }
+
+    @Test
+    void tokenize_umlautName_lowercasesToSingleToken() {
+        assertThat(PersonService.tokenize("Müller")).containsExactly("müller");
+    }
+
+    @Test
+    void tokenize_doubleSpace_dropsEmptyTokens() {
+        assertThat(PersonService.tokenize("Clara  Cram")).containsExactly("clara", "cram");
+    }
+
+    @Test
+    void tokenize_allWhitespace_returnsEmpty() {
+        assertThat(PersonService.tokenize("   ")).isEmpty();
+    }
+
+    @Test
+    void tokenize_null_returnsEmpty() {
+        assertThat(PersonService.tokenize(null)).isEmpty();
+    }
 }