Add session.Fork(n) and bump to 1.6.0-beta.13

Fork creates N sessions sharing cookies and TLS session caches but with
independent connections, simulating multiple browser tabs from the same
browser instance.

Add session.Warmup() and bump to 1.6.0-beta.12

Warmup simulates a real browser page load — fetches HTML, discovers
subresources (CSS, JS, images, fonts), and fetches them in batches
with Chrome-accurate headers, priorities, and timing. Cookies, TLS
sessions, cache state, and client hints accumulate naturally through
the existing Request() pipeline.

Wired through C FFI and all language bindings (Python, Node.js, .NET).

Bump NuGet version to 1.6.0-beta.11

Auto-cleanup proxy QUIC resources when connection dies

When a QUIC connection through SOCKS5 proxy closes (timeout, error, idle),
the associated quic.Transport and udpbara connection now get cleaned up
automatically via a goroutine watching conn.Context().Done().

Previously these resources only cleaned up on session.Close()/Refresh(),
so failed requests with retries + protocol fallback (H3→H2→H1) accumulated
leaked goroutines (quic.Transport reader + udpbara relay) that burned CPU
on Linux due to ECN/GSO syscalls on dead connections.

Fix quic.Transport goroutine leak in SOCKS5 H3 proxy path

Each dialQUICWithProxy call created a per-connection quic.Transport that
was never tracked or closed, leaking internal goroutines (packet reader,
timers). On Linux these goroutines spin on closed sockets after cleanup,
causing ~47% CPU on multi-core machines.

Fix: bundle each udpbara.Connection with its quic.Transport in a
proxyQUICConn struct so both are properly closed together — quic.Transport
first (sends CONNECTION_CLOSE), then udpbara (closes sockets).

Also remove the QUIC_GO_DISABLE_RECEIVE_BUFFER_WARNING suppression so
users see the warning when Linux UDP buffers are too small for QUIC.

Fix CI: run go mod tidy after dropping local replaces

The go.sum was generated with local replace directives and lacks checksums
for remote sardanioss/* modules. Running go mod tidy resolves them from
the Go proxy.

Bump NuGet version to 1.6.0-beta.7

Bump NuGet version to 1.6.0-beta.6

Add auto Content-Type detection for JSON POST bodies

When Post(), Request(), or their async/streaming variants are called with
a string body that starts with { or [, automatically set Content-Type to
application/json if not already set. Case-insensitive check for existing
Content-Type header. Does not affect byte[] body paths or override
explicitly set headers.

Fix clib version to 1.6.0-beta.4 and fix bogus fallback values in get…

…ter functions

httpcloak_version() was still returning "1.5.10". Also fixed
httpcloak_session_get_proxy/tcp_proxy/udp_proxy and
httpcloak_session_get_header_order which returned "1.5.10" as
fallback on nil session instead of proper error JSON.