add landlock support on linux landlock is applied only to the ui process to drop fs access and in the fs process to limit where telescope can read/write files. The network process is more difficult to landlock because while in theory it doesn't need *any* fs access, in practice it needs to read (at least) files inside /etc/ for DNS to work.

improve unveil' error reporting

fix sandbox wrt XDG-style directories

[openbsd] allow creation of files in ~/Downloads

(process) network -> net rename

ask to save a page when it can't be rendered it's good for thing like images and text with weird encodings.

don't include <err.h>, use the compat layer

fix various warnings, no functional changes now that we have a bounch of -Wxxx flags during compilation, let's fix everything.

adjust fs sandbox: allow writing and creating stuff into ~/.telescope

added fs process it's the only one that has file system access. For now it serves about:new (from memory) and about:bookmarks (from ~/.telescope/bookmarks.gmi if found)

sandbox ui process too

add required #include

Provide a stub for the sandbox

implement sandboxing for the network process on OpenBSD