fix: avoid macOS mDNS 5s delay on .local hosts entries

[kayjoosten]

If applied, this commit will make the documented /etc/hosts lines for the core and stepup environments resolve instantly on macOS instead of taking ~5 seconds per fresh hostname lookup.

Why is this change needed?
Prior to this change, the /etc/hosts lines had the IP address followed directly by a real hostname. On macOS, any .local hostname looked up this way is first tried via multicast DNS (Bonjour), which times out after ~5 seconds before falling back to /etc/hosts -- regardless of the entry being present. A typical login flow crosses several *.dev.openconext.local subdomains in sequence, so this tax stacks up to several seconds per redirect hop.

How does it address the issue?
Adds a throwaway alias word ("oc1"/"oc2") directly after the IP address on each affected line. A word in that position is enough to make macOS treat the line as a normal /etc/hosts entry and skip the mDNS attempt, cutting resolution to milliseconds. Updates both README.md files and the line init.sh prints during setup, with a short comment explaining why the leading word is there.

Links / references:
https://www.peterbe.com/plog/make-.local-domains-not-slow-in-macos

[kayjoosten]

Use ipv6 instead of the hack

[pmeulen]

Note that .local is a special-use domain name for hostnames on local networks that are resolved via Multicast DNS (RFC 6762). This explains the use of mDNS on systems that support it (like macOS). So the actual issue is/was that mDNS was used to resolve the IPv6 address of each *.dev.openconext.local domain, which has a 5 second timeout on OSX.

We however use .local like a private domain as-in (*.dev.openconext.local). There is historical precedent for this, but this causes name resolution side effects that will differ from device to device because of mDNS. The current best practice would be to use a .test TLD (RFC 6761), i.e. use *.openconext.test. Because of the switching costs involved I'd say we stay on .local for now.