Add TPP and TPP_DAG instructions

[rafaelha]

Generalized T gate analogous to Stim's SPP instruction. Phases the -1 eigenspace of Pauli product observables by exp(iπ/4) (or exp(-iπ/4) for TPP_DAG).

This would be a Tsim-only extension (not supported by Stim), following the same pattern as SPP/SPP_DAG but with T/T_DAG instead of S/S_DAG.

Since Stim doesn't know about TPP, parsing needs special handling — likely via the existing tag-based mechanism used for other custom gates (R_X, R_Y, etc.), or by extending the circuit parser to accept TPP directly.