fix: remove final dot in relay urls when doing https requests

[Frando]

Description

We append a final dot to all relay URL domains, to make sure that during DNS resolution the domain is treated as absolute, and no search suffix is appended. However, in the context of TLS name verification it is more correct to not have a final dot, so that the URL's hostname matches the name in the certificate. It seems this is not an issue with rustls, but when using openssl this is an issue (which we had reports for, but those are also fixed by #3486).

This PR adds methods to get the relay URL or hostname without the final dot, and uses those in the context of HTTPS requests.

Breaking Changes

Notes & open questions

Should check if there's more uses of those URLs. Likely we want to do the same when actually connecting to the relay? But didn't yet find the perfect spot for that.

Change checklist

• Self-review.
• Documentation updates following the style guide, if relevant.
• Tests if relevant.
• All breaking changes documented.
  • List all breaking changes in the above "Breaking Changes" section.
  • Open an issue or PR on any number0 repos that are affected by this breaking change. Give guidance on how the updates should be handled or do the actual updates themselves. The major ones are:
    • quic-rpc
    • iroh-gossip
    • iroh-blobs
    • dumbpipe
    • sendme

[github-actions]

Documentation for this PR has been generated and is available at: https://n0-computer.github.io/iroh/pr/3487/docs/iroh/

Last updated: 2025-09-30T11:08:23Z

[flub]

I'm kind of -0.5 on this.

1. It's brittle because we need to remember where to use which representation of the URL. Your comment already has questions about having found every spot.
2. #3486 already fixes this anyway.
3. The original reason for the final dot still applies, why let reqwest do the extra DNS lookups?

[github-actions]

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[dignifiedquire]

3. The original reason for the final dot still applies, why let reqwest do the extra DNS lookups?

From the investigation it sounded to melike that is not the case, the dot is removed by rustls at some point, so there seems to be no benefit in this case.

[flub]

3. The original reason for the final dot still applies, why let reqwest do the extra DNS lookups?

From the investigation it sounded to melike that is not the case, the dot is removed by rustls at some point, so there seems to be no benefit in this case.

@Frando correct me if I'm wrong, but I understood the dot is only removed to check whether the name on the certificate matches the dialed name. So that dot is left in-place for the dialing itself?

[ramfox]

closes #3377