Add case_delete: MCP tool + DELETE endpoint + DB helper

Wires a new case-deletion path across the three layers that needed it:

- db.delete_case(case_id) — single SQL DELETE; documents, chunks, and
  qa_results cascade via existing schema FKs, audit_log nullifies.
- cases_tools.case_delete(case_number, remove_files=False) — MCP tool
  wrapper. File tree on disk is kept by default (audit trail); pass
  remove_files=True for a hard delete.
- DELETE /api/cases?case_number=... — FastAPI endpoint taking the case
  number as a QUERY param rather than a path segment. Case numbers
  like "1000/0426" can't be passed through a path parameter because
  FastAPI routing decodes %2F before matching, so a query param is
  the only shape that works for historical data.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/server.py

@@ -102,6 +102,12 @@ async def case_update(
     )
 
 
+@mcp.tool()
+async def case_delete(case_number: str, remove_files: bool = False) -> str:
+    """מחיקת תיק ערר. קבצים בדיסק נשארים אלא אם remove_files=true."""
+    return await cases.case_delete(case_number, remove_files)
+
+
 # Documents
 @mcp.tool()
 async def document_upload(

mcp-server/src/legal_mcp/services/db.py

@@ -557,6 +557,16 @@ async def list_cases(status: str | None = None, limit: int = 50) -> list[dict]:
     return [_row_to_case(r) for r in rows]
 
 
+async def delete_case(case_id: UUID) -> bool:
+    """Delete a case. Dependent rows in documents/document_chunks/qa_results
+    cascade automatically (schema-level ON DELETE CASCADE); audit_log rows
+    nullify their case_id reference. Returns True if a row was deleted."""
+    pool = await get_pool()
+    async with pool.acquire() as conn:
+        result = await conn.execute("DELETE FROM cases WHERE id = $1", case_id)
+    return result.endswith(" 1")
+
+
 async def update_case(case_id: UUID, **fields) -> dict | None:
     if not fields:
         return await get_case(case_id)

mcp-server/src/legal_mcp/tools/cases.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import json
+import shutil
 import subprocess
 from pathlib import Path
 from uuid import UUID
@@ -214,3 +215,37 @@ async def case_update(
         )
 
     return json.dumps(updated, default=str, ensure_ascii=False, indent=2)
+
+
+async def case_delete(case_number: str, remove_files: bool = False) -> str:
+    """מחיקת תיק ערר. מסיר את התיק מ-DB עם cascade לכל המסמכים והטענות.
+
+    Args:
+        case_number: מספר תיק הערר
+        remove_files: האם למחוק גם את תיקיית הדיסק (drafts, git repo).
+                      ברירת מחדל False — ה-DB נמחק אבל הקבצים נשמרים לגיבוי.
+    """
+    case = await db.get_case_by_number(case_number)
+    if not case:
+        return json.dumps(
+            {"deleted": False, "reason": f"תיק {case_number} לא נמצא."},
+            ensure_ascii=False,
+        )
+
+    case_id = UUID(case["id"])
+    ok = await db.delete_case(case_id)
+
+    result = {
+        "deleted": ok,
+        "case_number": case_number,
+        "case_id": str(case_id),
+        "removed_files": False,
+    }
+
+    if ok and remove_files:
+        case_dir = config.find_case_dir(case_number)
+        if case_dir.exists():
+            shutil.rmtree(case_dir, ignore_errors=True)
+            result["removed_files"] = True
+
+    return json.dumps(result, ensure_ascii=False, indent=2)

web/app.py

@@ -1135,6 +1135,22 @@ async def api_case_update(case_number: str, req: CaseUpdateRequest):
         raise HTTPException(404, result)
 
 
+@app.delete("/api/cases")
+async def api_case_delete(case_number: str, remove_files: bool = False):
+    """Delete a case, identified by case_number in the query string.
+
+    Uses a query param (not a path segment) because case numbers may contain
+    characters like `/` that FastAPI path routing cannot capture even when
+    URL-encoded (%2F). Dependent documents/chunks/qa_results cascade via
+    FK ON DELETE CASCADE; audit_log rows nullify their case_id.
+    Pass `remove_files=true` to also rm -rf the on-disk case directory."""
+    result = await cases_tools.case_delete(case_number, remove_files)
+    data = json.loads(result)
+    if not data.get("deleted"):
+        raise HTTPException(404, data.get("reason", f"תיק {case_number} לא נמצא"))
+    return data
+
+
 @app.get("/api/cases/{case_number}/status")
 async def api_case_status(case_number: str):
     """Get full workflow status for a case."""