adds --dump screen.pdf and CDP's Page.printToPDF (along with IO.read and
IO.read). Builds ontop of https://github.com/lightpanda-io/browser/pull/3231
This generates a text-based PDF, not just our PNG placed into a PDF. The biggest
change to the existing (isolated) code was adding href information so that links
are actually clickable.
Like 3231 the hard parts are all Claude but isolated. The one place it diverged
from the plan was NOT using the subsetter rust crate for trimming the size of
the embedded font. It felt that the dependencies were too much (e.g. a second
version of skrifa, ...). One subsetter was removed, the pdf rendering, while
still a blackbox, was moved from Rust to Zig (pdf.zig), which is kind of nice.
Remove singleton and give each Browser a screenshot.Renderer.
Also, add tests to make sure the Rust and Zig structures/constants match (this
has proven useful with zig-v8-fork).
Return (height, rc) rather than just height, so that we can correctly detect
a failed raster (which still produced a height). Also add constants for error
codes rather than magic numbers sprinkled here and there.
Karl Seguin