fix: prefer Yamux transport for headless account selection

[cray-com]

Summary

• prefer Yamux/TCP when the headless CLI selects an existing bot account
• preserve all existing AccountSelect request fields through a small request builder
• add a regression test covering the transport preference and custom-network fields

Root cause and reproduction

anytype-heart exposes PreferYamuxTransport specifically for clients that have problems with QUIC, but the headless CLI never enabled it during bot-account auto-login. On a native Linux x86_64 VPS using the public Anytype Network, a fresh active member invite produced:

Failed to view invite: failed to view space invite:
rpc error: code = DeadlineExceeded desc = stream terminated by RST_STREAM with error code: CANCEL

A/B test with the same account and invite:

• upstream QUIC account selection: failed after 5.059s
• Yamux/TCP account selection: invite viewed and join request sent successfully in 0.267s
• after owner approval, the joined space and editor membership were readable through the REST API

This also matches the existing escape-hatch comment in anytype-heart: Yamux is intended for clients that encounter QUIC problems.

Verification

• new regression test observed failing before implementation
• sabotage run confirmed the test fails when PreferYamuxTransport is false
• make test
• go vet ./...
• separate binary build
• live end-to-end invite join against the public Anytype Network
• independent pre-commit review: no security or logic findings

Fixes #36