chore: prepare version 3.3.5

[regyssilveira]

Summary

Prepare Horse 3.3.5 by updating the public version constant and Boss manifest from 3.3.4 to 3.3.5.

Why a patch release

Horse 3.3.4 enabled FPC keep-alive across platforms, but its no-delay socket handler remained Unix-only. The follow-up fix in #566 restores FPC 3.3.1+ Windows compilation and applies TCP_NODELAY to reused Windows connections. This release also includes the FPC/epoll WebSocket EAGAIN regression gate from #564.

Validation

• 74/74 compile-matrix combinations passed across Delphi 10, 11, 12, 13 and FPC/Linux.
• 24/24 Delphi DUnitX provider/router combinations passed; Delphi 11/HttpSys had one transient integration run failure and passed 207/207 on an immediate clean isolated rerun.
• FPC 3.2.2 WebSocket/epoll regression: 5/5 checks passed in Docker.
• FPC trunk 3.3.1 keep-alive regression on Linux: median 0.153 ms, p95 0.274 ms.
• FPC trunk 3.3.1 Win64 cross-build executed natively on Windows: median 0.249 ms, p95 0.384 ms.
• boss.json parsed successfully and the workflow passed actionlint.