LangevinFlow 0.1.0

• First CRAN submission.
• Implements the Unadjusted Langevin Algorithm (ula()) and the Metropolis-Adjusted Langevin Algorithm (mala()) with a C++ backend using Rcpp and RcppArmadillo.
• Provides an S3 class "langevin_chain" with print(), summary(), and plot() methods.
• All random number generation is routed through R’s RNG state, so set.seed() controls reproducibility of the chains.