feat: completude de l'editeur Excel - mise en forme, sortie, concurrence, cache, outils IA #156

L'editeur lisait les styles mais ne les ecrivait pas, exportait la feuille
entiere et laissait le dernier-ecrivain gagner entre processus.

- A8 : bouton Mise en forme (gras/italique/souligne, alignements, couleurs via
  selecteur natif, formats de nombre, fusion, volets figes, largeur/hauteur) et
  nouvelle route PUT .../xlsx/style (verrou, backup, swap atomique, garde de
  perte, If-Match) ; A9 : decision "pas de moteur de formule" annoncee dans
  l'UI ; A10 : undo/redo unifie, piles par fichier conservees au re-rendu
- A11 : export de la selection + Markdown/HTML/impression et recherche sur
  toutes les feuilles ; A12 : concurrence optimiste (If-Match -> 409 reparable,
  retry qui relit) ; A13 : cache des metadonnees par (chemin, mtime, taille)
- A14 : outils IA .xlsm/.csv + search_workbook, analyze_range,
  edit_xlsx_structure
- tests : test_xlsx_styles.py (17), test_spreadsheet_tools.py (34),
  TestOptimisticConcurrency/TestMetaCache, JSDOM xlsx-viewer 107/107

tests/test_xlsx_formats.py

@@ -95,9 +95,32 @@ class TestXlsmEditable:
         with zipfile.ZipFile(_vault_file(client, xlsm_book)) as zf:
             assert "xl/vbaProject.bin" in zf.namelist()
 
-    def test_lossy_gate_is_skipped_for_xlsm(self, formats_vault, xlsm_book):
+    def test_sheet_window_is_served_for_xlsm(self, client, xlsm_book):
+        """BUG-097 — a .xlsm is editable, so its lazy row windows must work."""
+        resp = client.get(
+            f"/api/file/{VAULT}/xlsx/sheet",
+            params={"path": xlsm_book, "sheet": "Data", "offset": 0, "limit": 100},
+        )
+        assert resp.status_code == 200, resp.text
+        body = resp.json()
+        assert body["sheet"] == "Data"
+        assert 'data-cell="A2"' in body["html"]
+        assert body["has_more"] is False
+
+    def test_sheet_window_still_refuses_other_formats(self, client, formats_vault):
+        (formats_vault / "plain.csv").write_text("a,b\n", encoding="utf-8")
+        resp = client.get(
+            f"/api/file/{VAULT}/xlsx/sheet",
+            params={"path": "plain.csv", "sheet": "Feuille1"},
+        )
+        assert resp.status_code == 415
+
+    def test_lossy_gate_is_skipped_for_xlsm(self, client, formats_vault, xlsm_book):
         from backend.services.mutations import edit_xlsx_cells
 
+        # `client` is required: the service resolves the vault through the app
+        # registry (the test used to pass only thanks to state leaked by an
+        # earlier test in this class).
         # No force flag: the save must succeed despite the vbaProject part
         # (it would raise xlsx_lossy_content on a plain .xlsx).
         result = edit_xlsx_cells(VAULT, xlsm_book, "Data", {"A2": "Alan"})
@@ -149,6 +172,22 @@ class TestLegacyReadOnly:
         assert sheet["rows"] == 0
 
 
+class TestCsvDelimiter:
+    """BUG-098 — the delimiter is detected, not assumed to be a comma."""
+
+    def test_sniffing_handles_the_common_separators(self):
+        from backend.xlsx_reader import sniff_csv_delimiter
+
+        assert sniff_csv_delimiter("a;b\n1;2\n") == ";"
+        assert sniff_csv_delimiter("a,b\n1,2\n") == ","
+        assert sniff_csv_delimiter("a\tb\n1\t2\n") == "\t"
+
+    def test_single_column_falls_back_to_a_comma(self):
+        from backend.xlsx_reader import sniff_csv_delimiter
+
+        assert sniff_csv_delimiter("juste\nune\ncolonne\n") == ","
+
+
 class TestCsvEditable:
     def test_read_renders_the_xlsx_shaped_table(self, client, formats_vault):
         (formats_vault / "liste.csv").write_text("a,b\n1,2\n", encoding="utf-8")
@@ -197,6 +236,42 @@ class TestCsvEditable:
         text = _vault_file(client, "quotes.csv").read_text(encoding="utf-8")
         assert '"Martin, Pierre"' in text
 
+    def test_semicolon_csv_renders_multiple_columns(self, client, formats_vault):
+        """BUG-098 — a French (semicolon) CSV is no longer a single column."""
+        (formats_vault / "fr.csv").write_text("Nom;Ville\nAda;Paris\n", encoding="utf-8")
+        html = client.get(
+            f"/api/file/{VAULT}", params={"path": "fr.csv"}
+        ).json()["html"]
+        assert 'data-cell="B1"' in html and 'data-cell="B2"' in html
+        assert "Paris" in html
+
+    def test_semicolon_is_preserved_when_saving(self, client, formats_vault):
+        """BUG-098 — the write-back keeps the file's own delimiter."""
+        (formats_vault / "fr.csv").write_text("Nom;Ville\nAda;Paris\n", encoding="utf-8")
+        resp = client.put(
+            f"/api/file/{VAULT}/csv/save",
+            params={"path": "fr.csv"},
+            json={"cells": {"B2": "Lyon"}},
+        )
+        assert resp.status_code == 200
+        text = _vault_file(client, "fr.csv").read_text(encoding="utf-8")
+        assert "Nom;Ville" in text
+        assert "Ada;Lyon" in text
+        assert "," not in text  # the source delimiter is not switched to a comma
+
+    def test_quoted_semicolon_survives_a_round_trip(self, client, formats_vault):
+        (formats_vault / "quote-fr.csv").write_text(
+            'Nom;Note\n"Dupont; Jean";ok\n', encoding="utf-8"
+        )
+        client.put(
+            f"/api/file/{VAULT}/csv/save",
+            params={"path": "quote-fr.csv"},
+            json={"cells": {"B2": "modifié"}},
+        )
+        text = _vault_file(client, "quote-fr.csv").read_text(encoding="utf-8")
+        assert '"Dupont; Jean"' in text
+        assert ";modifié" in text
+
     def test_bad_reference_is_refused(self, client, formats_vault):
         (formats_vault / "liste.csv").write_text("a\n", encoding="utf-8")
         resp = client.put(