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

backend/tools/schemas.py

@@ -332,12 +332,42 @@ class XlsxToMarkdownInput(BaseModel):
     )
 
 
+class SearchWorkbookInput(BaseModel):
+    """Find a text across the sheets of a spreadsheet (#156 A14)."""
+
+    vault: str = Field(..., description="Vault name")
+    path: str = Field(
+        ..., description="Vault-relative path of the file (.xlsx, .xlsm or .csv)"
+    )
+    query: str = Field(..., description="Text to look for")
+    sheet: str = Field("", description="Restrict to one sheet (empty = all sheets)")
+    case_sensitive: bool = Field(False, description="Match case")
+
+
+class AnalyzeRangeInput(BaseModel):
+    """Aggregate the values of an A1 range (#156 A14)."""
+
+    vault: str = Field(..., description="Vault name")
+    path: str = Field(
+        ..., description="Vault-relative path of the file (.xlsx, .xlsm or .csv)"
+    )
+    sheet: str = Field(
+        "", description="Sheet name (empty = the first/active sheet)"
+    )
+    range: str = Field(
+        "",
+        description="A1 range to analyse (e.g. 'B2:B50'); empty = the whole sheet",
+    )
+
+
 class UpdateXlsxCellsInput(BaseModel):
     """Batch-edit cells of an existing .xlsx workbook (#153 A6)."""
 
     vault: str = Field(..., description="Vault name")
     path: str = Field(..., description="Vault-relative path of the .xlsx file")
-    sheet: str = Field(..., description="Worksheet title to edit")
+    sheet: str = Field(
+        "", description="Worksheet title to edit (ignored for a .csv)"
+    )
     cells: dict[str, str | int | float | bool | None] = Field(
         ..., description="A1 reference -> new value (max 500 per call)"
     )
@@ -370,6 +400,25 @@ class AppendXlsxRowsInput(BaseModel):
     )
 
 
+class EditXlsxStructureInput(BaseModel):
+    """Structural CRUD on an existing workbook (#156 A14)."""
+
+    vault: str = Field(..., description="Vault name")
+    path: str = Field(..., description="Vault-relative path of the .xlsx/.xlsm file")
+    actions: list[dict[str, Any]] = Field(
+        ...,
+        description=(
+            "Ordered structural actions (1-50): sheet_add/sheet_rename/"
+            "sheet_duplicate/sheet_delete, row_insert/row_delete/"
+            "col_insert/col_delete"
+        ),
+    )
+    force: bool = Field(
+        False,
+        description="Write even when features openpyxl cannot rewrite would be dropped",
+    )
+
+
 class CsvInput(BaseModel):
     """Create a .csv file in a vault from rows of cells."""