Fix: Restore program as required field for cppdbg attach configurations

MIEngine requires the program field for gdb/lldb debugging even in attach mode.
Without it, debugging fails after the debugger starts. The program field serves
dual purpose: finding the process by name (new feature) and providing symbol
information to the debugger (existing MIEngine requirement).

Updated documentation to clarify that program is required and explain why.

Author: Subham-KRLX

Extension/package.json

@@ -4770,7 +4770,9 @@
                     "attach": {
                         "type": "object",
                         "default": {},
-                        "required": [],
+                        "required": [
+                            "program"
+                        ],
                         "properties": {
                             "targetArchitecture": {
                                 "type": "string",

Extension/package.nls.json

@@ -932,9 +932,9 @@
         ]
     },
     "c_cpp.debuggers.program.attach.markdownDescription": {
-        "message": "Optional full path to the program executable. When specified, the debugger will search for a running process matching this executable path and attach to it. If multiple processes match, a selection prompt will be shown. Use either `program` or `processId`, not both.",
+        "message": "Full path to the program executable. The debugger will search for a running process matching this executable path and attach to it. If multiple processes match, a selection prompt will be shown. This field is required to load debug symbols for the attached process.",
         "comment": [
-            "{Locked=\"`program`\"} {Locked=\"`processId`\"}"
+            "{Locked=\"`program`\"}"
         ]
     },
     "c_cpp.debuggers.symbolSearchPath.description": "Semicolon separated list of directories to use to search for symbol (that is, pdb or .so) files. Example: \"c:\\dir1;c:\\dir2\".",