SimpleSallap:SimpleMCP:Body Bytes to Json within mcp_run

Given that there could be other service paths beyond /mcp exposed
in future, and given that it is not necessary that their post body
contain json data, so move conversion to json to within mcp_run
handler.

While retaining reading of the body in the generic do_POST ensures
that the read size limit is implicitly enforced, whether /mcp now or
any other path in future.

tools/server/public_simplechat/local.tools/simplemcp.py

@@ -122,7 +122,8 @@ class ProxyHandler(http.server.BaseHTTPRequestHandler):
         tcl = mTC.MCPToolsList(oRPC["id"], mTC.MCPTLResult(gMe.op.toolManager.meta()))
         self.send_mcp(200, "tools/list follows", tcl)
 
-    def mcp_run(self, oRPC: Any):
+    def mcp_run(self, body: bytes):
+        oRPC = json.loads(body)
         if oRPC["method"] == "tools/call":
             self.mcp_toolscall(oRPC)
         elif oRPC["method"] == "tools/list":
@@ -140,14 +141,13 @@ class ProxyHandler(http.server.BaseHTTPRequestHandler):
         if not acGot.callOk:
             self.send_error(acGot.statusCode, acGot.statusMsg)
         pr = urllib.parse.urlparse(self.path)
-        print(f"DBUG:ProxyHandler:GET:{pr}")
+        print(f"DBUG:PH:Post:{pr}")
         if pr.path != '/mcp':
             self.send_error(400, f"WARN:UnknownPath:{pr.path}")
         body = self.rfile.read(gMe.nw.maxReadBytes)
         if len(body) == gMe.nw.maxReadBytes:
             self.send_error(400, f"WARN:RequestOverflow:{pr.path}")
-        oRPC = json.loads(body)
-        self.mcp_run(oRPC)
+        self.mcp_run(body)
 
     def do_POST(self):
         """