Provide GoDoc generation

[Vladyslav-Kuksiuk]

This PR provide GoDoc API generation configuration.

Resolves this issue.

[Oleg-Melnik]

Claude Review

Note — GODOC_GOCACHE uses a fixed, shared /tmp path

scripts/godoc and scripts/godoc-serve both default:

: "${GODOC_GOCACHE:=/tmp/embed-code-go-godoc-cache}"

This is a predictable path shared across all users of the machine. On a multi-user host, if the cache directory already exists and is owned by another user, go/godoc will fail with a permission error. It's also a mildly unsafe predictable temp location.

Prefer a per-user or randomized path, e.g.:

: "${GODOC_GOCACHE:=${TMPDIR:-/tmp}/embed-code-go-godoc-cache-$USER}"

or mktemp -d. Not blocking — just a robustness improvement.

[Oleg-Melnik]

@Vladyslav-Kuksiuk LGTM with a comment to address.