* tor-snowflake: read the Go version from the module root
Snowflake is a single Go module with go.mod at the repository root, not
under proxy/. The install read /opt/tor-snowflake/proxy/go.mod, which
has never existed, so grep failed and the version came out empty. Go
was then fetched from
https://go.dev/dl/go.linux-amd64.tar.gz
with no version in the name, and the install aborted at that download.
Read the directive with a single awk instead of grep piped into awk.
The pipeline tripped catch_errors, which sets -Ee with pipefail and an
ERR trap, the moment the file was missing; that is the "exit code 2
while executing command awk" line that preceded the download failure.
Fall back to latest when the file cannot be read, so a future upstream
move of go.mod costs a Go version that is newer than the one pinned
rather than a failed build. setup_go already resolves latest, and also
resolves a bare major.minor to its newest patch, so a go directive
without a patch level stays fine.
Verified against v2.14.1: go.mod sits at the root and declares go
1.24.0, and the awk yields 1.24.0 from it and latest from a missing
file without tripping the ERR trap.
* Refactor GO_VERSION extraction in tor-snowflake.sh
Updated the method of extracting GO_VERSION from go.mod and set a default value if not found.
