Fixes #819

Context: Some hosts can cause the auto→openssl fallback path to hang indefinitely. The underlying dial uses context.TODO(), so a stuck connect can block the entire scan.

Changes:

• Use a unified context.WithTimeout to bound both the dial and the openssl execution path.
• This prevents indefinite hangs and makes behavior consistent with other timeout-controlled code paths.

Tests:

• go test ./… -run “^$” -count=1 (build-only)

/claim #819