style: Format code with Black

Applied Black code formatter to fix CI formatting checks:
- src/dap_stdio_client.py
- src/mcp_server.py
- tests/test_improved_error_handling.py

This resolves the failing CI check for code formatting.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: markomanninen

src/dap_stdio_client.py

@@ -253,16 +253,16 @@ async def _recv(self) -> Dict[str, Any]:
                 message = "Debug adapter connection closed"
                 if exit_code is not None:
                     if exit_code == 0:
-                        message += f" (program exited successfully with code {exit_code})"
+                        message += (
+                            f" (program exited successfully with code {exit_code})"
+                        )
                     else:
                         message += f" (program crashed with exit code {exit_code})"
 
                 if detail:
                     message = f"{message}.\nAdapter stderr:\n{detail}"
 
-                message += (
-                    "\n\nTip: Use stop_on_entry=True or verify breakpoints are on executable lines"
-                )
+                message += "\n\nTip: Use stop_on_entry=True or verify breakpoints are on executable lines"
                 raise EOFError(message)
             if line == b"\r\n":
                 break

src/mcp_server.py

@@ -946,7 +946,9 @@ async def dap_validate_breakpoint_line(source_path: str, line: int) -> Dict[str,
             for i in range(line, min(line + 5, len(lines))):
                 next_line = lines[i].strip()
                 if next_line and not next_line.startswith("#"):
-                    preview = next_line[:50] + "..." if len(next_line) > 50 else next_line
+                    preview = (
+                        next_line[:50] + "..." if len(next_line) > 50 else next_line
+                    )
                     suggestions.append(f"Consider line {i + 1}: {preview}")
                     break
 

tests/test_improved_error_handling.py

@@ -1,4 +1,5 @@
 """Tests for improved error handling and validation features."""
+
 import asyncio
 import tempfile
 from pathlib import Path