Odd-weight parabolic cohomology bound at levels three and four

For $N\in\{3,4\}$ and an odd weight $k\ge3$, the parabolic cohomology of $\Gamma_1(N)$ with degree-$k-2$ binary-form coefficients has complex dimension at most twice the dimension of $S_k(\Gamma_1(N))$. Parabolic cocycles restrict to principal cocycles on every rational cusp stabilizer, and cohomology is taken modulo principal cocycles. This is the odd-weight part of the remaining small-level dimension input in the MTT mission. Unlike the even-weight case, this cannot be obtained from the trivial-nebentypus Gamma0 theorem merely by adjoining the central sign; the elliptic and irregular-cusp contributions must be treated correctly.