refactor: remove Endpoint::conn_type

[Frando]

Description

• Remove Endpoint::conn_type
• Update transfer.rs example to use Connection::paths instead
• Change return type of Connection::paths to have more guarantees on the return type (Send, Unpin, 'static)

Breaking Changes

Notes & open questions

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/3647/docs/iroh/

Last updated: 2025-11-11T13:23:51Z

[github-actions]

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Last updated for commit: d7380ff