如果函数\(y=f\left(x\right) \)的定义域为\(R\),对于定义域内的任意\(x\),存在实数\(a\)使得\(f\left(x+a\right)=f\left(-x\right) \)成立,则称此函数具有“\(P\left(a\right) \)性质”.
\((\)Ⅰ\()\)判断函数\(y=\sin x \)是否具有“\(P\left(a\right) \)性质”,若具有“\(P\left(a\right) \)性质”求出所有\(a\)的值;若不具有“\(P\left(a\right) \)性质”,请说明理由.
\((\)Ⅱ\()\)已知\(y=f\left(x\right) \)具有“\(P\left(0\right) \)性质”,且当\(x\leqslant 0 \)时\(f\left(x\right)={\left(x+m\right)}^{2} \),求\(y=f\left(x\right) \)在\(\left[0,1\right] \)上的最大值.
\((\)Ⅲ\()\)设函数\(y=g\left(x\right) \)具有“\(P\left(±1\right) \)性质”,且当\(- \dfrac{1}{2}\leqslant x\leqslant \dfrac{1}{2} \)时,\(g\left(x\right)=\left|x\right| .\)若\(y=g\left(x\right) \)与\(y=mx \)交点个数为\(2013\)个,求\(m\)的值.