feat: Alpha-ID-SE corpus parser with code normalization

tests/corpus_tests.rs

@@ -0,0 +1,29 @@
+use alpha_id::corpus;
+
+#[test]
+fn parses_pipe_line_into_entry() {
+    let line = "1|I69812|A01.0+|I39.8*|||99745|Typhus-Endokarditis";
+    let e = corpus::parse_line(line).expect("should parse");
+    assert_eq!(e.alpha_id, "I69812");
+    assert!(e.valid);
+    assert_eq!(e.icd_primary, "A01.0"); // normalized: no '+'
+    assert_eq!(e.icd_star, "I39.8");    // normalized: no '*'
+    assert_eq!(e.orpha, "99745");
+    assert_eq!(e.text, "Typhus-Endokarditis");
+}
+
+#[test]
+fn invalid_flag_is_false() {
+    let line = "0|I97837|||U81!|||Bakterien mit Multiresistenz";
+    let e = corpus::parse_line(line).unwrap();
+    assert!(!e.valid);
+    assert_eq!(e.icd_addon, "U81"); // field 5, '!' stripped
+    assert_eq!(e.icd_primary, "");
+}
+
+#[test]
+fn loads_full_real_corpus() {
+    let entries = corpus::load("data/icd10gm2026_alphaidse_edvtxt_20250926.txt").unwrap();
+    assert_eq!(entries.len(), 90_898);
+    assert!(entries.iter().any(|e| e.text.contains("Diabetes mellitus Typ 2")));
+}