Summary: The answer to the first question is no. See Robert Israel's answer for the periodic case.
A bounded analytic function $f$ on the open upper-half plane induces a bounded analytic function $\tilde f$ on the open unit disk $D$ via the Cayley transform, such that if $f$ has a continuous extension to $\mathbb R$, then $\tilde f$ has a continuous extension to $\partial D\setminus\{1\}$. However, using Blaschke products, one can give examples of bounded analytic functions on the open unit disk that have no such extension. All bounded analytic functions have nontangential limiting values a.e. on the boundary, and in the case of Blaschke products the boundary functions that come from these limits have modulus $1$ a.e. On the other hand, the set of zeros of a Blaschke product can be chosen to contain the boundary in its closure, so any continuous extension would have to vanish on the boundary, and hence can't exist. See also Myke's related question on the case of the disk.
Robert Israel's answer covers the periodic case, but here is a general fact about bounded analytic periodic functions that might be useful. On page 183 of Gamelin's Complex analysis it is shown under a weaker hypothesis that such $f$ has a pointwise absolutely convergent series expansion in the open half-plane, $f(z)=\sum\limits_{k=0}^\infty a_ke^{2\pi i kz}$, converging uniformly on each half-plane $\mathrm{Im}\ z\geq \varepsilon>0$.
You can find much more in Garnett's Bounded analytic functions. For example, a necessary and sufficient condition for a sequence $(z_n)_n$ to be the set of zeros of some nonconstant bounded analytic function on the open half plane is that $\sum_n\frac{\mathrm{Im}\ z_n}{1+|z_n|^2}<\infty,$ as seen on page 53 of Garnett. So the set of zeros of a nonconstant bounded analytic function can be chosen to contain $\mathbb R$ in its closure, implying that if there were a continuous extension it would have to vanish on $\mathbb R$. But in Section II.4 it is shown that the boundary function $f:\mathbb R\to\mathbb C$ of a nonconstant analytic function with continuous extension to the real line must satisfy $\int_{\mathbb R}\frac{\log|f(t)|}{1+t^2}dt>-\infty,$ implying that $f$ is nonvanishing off a set of measure $0$.