fix(vpi): count a static method's first parameter as an argument

LookupSignDefaultsByName subtracted one receiver slot from every class-level def, but the vpi keeps the declared parameter list: a @staticmethod's first parameter is a real argument. Scheduler.exit_process(pid: int) therefore reported 0 parameters and the call-site arity check rejected exit_process(p.pid). Subtract the receiver only when the first parameter is actually named self/cls.

App/lib/Stub/StubGen/VpiReader.vp

@@ -2953,19 +2953,43 @@ def LookupSignDefaultsByName(pool: memhub.MemBuddy*, sha1: str, name: str, kinds
     if parse_defaults == 0:
         # 只数形参个数（含可变参数则放弃：调用方跳过 arity 校验）
         pc_only: int = _VpiParamCountAndVararg(vbuf, hit_ps, hit_pe)
+        self_only: int = 0
+        if pc_only > 0 and hit_method != 0:
+            if _VpiFirstParamIsSelf(vbuf, hit_ps, hit_pe) != 0: self_only = 1
         stdlib.free(vbuf)
         if pc_only < 0: return -1
-        if hit_method != 0 and pc_only > 0: pc_only -= 1
+        if self_only != 0: pc_only -= 1
         return pc_only << 8
     enc: int = _VpiParseParamDefaults(pool, vbuf, hit_ps, hit_pe, kinds, ints, strs)
+    self_f: int = 0
+    if hit_method != 0 and _VpiFirstParamIsSelf(vbuf, hit_ps, hit_pe) != 0: self_f = 1
     stdlib.free(vbuf)
     if enc < 0: return -1
     pc_f: int = enc >> 8
     dc_f: int = enc & 0xFF
-    if hit_method != 0 and pc_f > 0: pc_f -= 1
+    if self_f != 0 and pc_f > 0: pc_f -= 1
     return (pc_f << 8) | dc_f
 
 
+# _VpiFirstParamIsSelf - 1 when the first parameter listed in [ps, pe) is named self/cls.
+# Only those methods carry a receiver slot; a `@staticmethod` whose first parameter is a real
+# argument must not have one subtracted from its parameter count.
+def _VpiFirstParamIsSelf(buf: bytes, ps: sizet, pe: sizet) -> int:
+    """1 when the first parameter in the vpi text range is named self or cls."""
+    if buf is None or pe <= ps: return 0
+    i: sizet = ps
+    while i < pe and (buf[i] == 0x20 or buf[i] == 0x09): i += 1
+    s: sizet = i
+    while i < pe:
+        ch: char = buf[i]
+        if ch == ':' or ch == '=' or ch == ',' or ch == ')' or ch == 0x20 or ch == 0x09: break
+        i += 1
+    n: sizet = i - s
+    if n == 4 and string.strncmp(buf + s, "self", 4) == 0: return 1
+    if n == 3 and string.strncmp(buf + s, "cls", 3) == 0: return 1
+    return 0
+
+
 # LookupParamCountByName - 取定义模块 .vpi 里某函数/方法的形参个数（方法不含 self）
 # 返回 -1 表示未找到或签名含可变参数（调用方应跳过 arity 校验）。
 def LookupParamCountByName(pool: memhub.MemBuddy*, sha1: str, name: str) -> int: