The DAP TCP transport layer was hardcoded to `Ipv4Addr`, so IPv6
addresses like `fd00::a` in a debug config's `connect.host` always
failed with `hostname must be IPv4: invalid IPv4 address syntax`.

Replaced `Ipv4Addr` with `IpAddr` and `SocketAddrV4` with `SocketAddr`
across the `task`, `dap`, `dap_adapters`, and `project` crates. The WASM
extension API still uses `u32` for the host field to avoid a breaking
WIT interface change; IPv4 round-trips through extensions as before.

Fixes #52237

Release Notes:

- Fixed DAP TCP transport rejecting IPv6 addresses when connecting to
remote debug adapters.

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Co-authored-by: moktamd <moktamd@users.noreply.github.com>