Upgrade net package from Go 1.21.4 to Go 1.26.2

Backport upstream Go standard library changes to TinyGo's net package.

Unmodified files (18) replaced directly from Go 1.26.2 source.
Modified files (22) merged via 3-way diff, preserving all TinyGo
netdev adaptations, TINYGO markers, and embedded-device constraints.

Notable upstream changes included:
- net/http: cookie handling improvements, fs enhancements,
  reverse proxy updates, chunked encoding fixes
- net/http: ServeMux routing and pattern matching updates
- net: IP parsing and MAC address handling improvements
- Various doc link syntax modernization (e.g. [Dial], [Buffers])

TinyGo-only files (netdev.go, tlssock.go) unchanged.
All TINYGO comment markers preserved.

http/http.go

@@ -1,10 +1,8 @@
-// TINYGO: The following is copied from Go 1.21.4 official implementation.
-
-// Copyright 2016 The Go Authors. All rights reserved.
+// TINYGO: The following is copied from Go 1.26.2 official implementation.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:generate bundle -o=h2_bundle.go -prefix=http2 -tags=!nethttpomithttp2 golang.org/x/net/http2
+//go:generate bundle -o=h2_bundle.go -prefix=http2 -tags=!nethttpomithttp2 -import=golang.org/x/net/internal/httpcommon=net/http/internal/httpcommon golang.org/x/net/http2
 
 package http
 
@@ -18,6 +16,67 @@ import (
 	"golang.org/x/net/http/httpguts"
 )
 
+// Protocols is a set of HTTP protocols.
+// The zero value is an empty set of protocols.
+//
+// The supported protocols are:
+//
+//   - HTTP1 is the HTTP/1.0 and HTTP/1.1 protocols.
+//     HTTP1 is supported on both unsecured TCP and secured TLS connections.
+//
+//   - HTTP2 is the HTTP/2 protcol over a TLS connection.
+//
+//   - UnencryptedHTTP2 is the HTTP/2 protocol over an unsecured TCP connection.
+type Protocols struct {
+	bits uint8
+}
+
+const (
+	protoHTTP1 = 1 << iota
+	protoHTTP2
+	protoUnencryptedHTTP2
+)
+
+// HTTP1 reports whether p includes HTTP/1.
+func (p Protocols) HTTP1() bool { return p.bits&protoHTTP1 != 0 }
+
+// SetHTTP1 adds or removes HTTP/1 from p.
+func (p *Protocols) SetHTTP1(ok bool) { p.setBit(protoHTTP1, ok) }
+
+// HTTP2 reports whether p includes HTTP/2.
+func (p Protocols) HTTP2() bool { return p.bits&protoHTTP2 != 0 }
+
+// SetHTTP2 adds or removes HTTP/2 from p.
+func (p *Protocols) SetHTTP2(ok bool) { p.setBit(protoHTTP2, ok) }
+
+// UnencryptedHTTP2 reports whether p includes unencrypted HTTP/2.
+func (p Protocols) UnencryptedHTTP2() bool { return p.bits&protoUnencryptedHTTP2 != 0 }
+
+// SetUnencryptedHTTP2 adds or removes unencrypted HTTP/2 from p.
+func (p *Protocols) SetUnencryptedHTTP2(ok bool) { p.setBit(protoUnencryptedHTTP2, ok) }
+
+func (p *Protocols) setBit(bit uint8, ok bool) {
+	if ok {
+		p.bits |= bit
+	} else {
+		p.bits &^= bit
+	}
+}
+
+func (p Protocols) String() string {
+	var s []string
+	if p.HTTP1() {
+		s = append(s, "HTTP1")
+	}
+	if p.HTTP2() {
+		s = append(s, "HTTP2")
+	}
+	if p.UnencryptedHTTP2() {
+		s = append(s, "UnencryptedHTTP2")
+	}
+	return "{" + strings.Join(s, ",") + "}"
+}
+
 // incomparable is a zero-width, non-comparable type. Adding it to a struct
 // makes that struct also non-comparable, and generally doesn't add
 // any size (as long as it's first).
@@ -60,8 +119,10 @@ func removeEmptyPort(host string) string {
 	return host
 }
 
-func isNotToken(r rune) bool {
-	return !httpguts.IsTokenRune(r)
+// isToken reports whether v is a valid token (https://www.rfc-editor.org/rfc/rfc2616#section-2.2).
+func isToken(v string) bool {
+	// For historical reasons, this function is called ValidHeaderFieldName (see issue #67031).
+	return httpguts.ValidHeaderFieldName(v)
 }
 
 // stringContainsCTLByte reports whether s contains any ASCII control character.
@@ -105,10 +166,10 @@ func hexEscapeNonASCII(s string) string {
 	return string(b)
 }
 
-// NoBody is an io.ReadCloser with no bytes. Read always returns EOF
+// NoBody is an [io.ReadCloser] with no bytes. Read always returns EOF
 // and Close always returns nil. It can be used in an outgoing client
 // request to explicitly signal that a request has zero bytes.
-// An alternative, however, is to simply set Request.Body to nil.
+// An alternative, however, is to simply set [Request.Body] to nil.
 var NoBody = noBody{}
 
 type noBody struct{}
@@ -123,7 +184,7 @@ var (
 	_ io.ReadCloser = NoBody
 )
 
-// PushOptions describes options for Pusher.Push.
+// PushOptions describes options for [Pusher.Push].
 type PushOptions struct {
 	// Method specifies the HTTP method for the promised request.
 	// If set, it must be "GET" or "HEAD". Empty means "GET".
@@ -165,3 +226,81 @@ type Pusher interface {
 	// is not supported on the underlying connection.
 	Push(target string, opts *PushOptions) error
 }
+
+// HTTP2Config defines HTTP/2 configuration parameters common to
+// both [Transport] and [Server].
+type HTTP2Config struct {
+	// MaxConcurrentStreams optionally specifies the number of
+	// concurrent streams that a client may have open at a time.
+	// If zero, MaxConcurrentStreams defaults to at least 100.
+	//
+	// This parameter only applies to Servers.
+	MaxConcurrentStreams int
+
+	// StrictMaxConcurrentRequests controls whether an HTTP/2 server's
+	// concurrency limit should be respected across all connections
+	// to that server.
+	// If true, new requests sent when a connection's concurrency limit
+	// has been exceeded will block until an existing request completes.
+	// If false, an additional connection will be opened if all
+	// existing connections are at their limit.
+	//
+	// This parameter only applies to Transports.
+	StrictMaxConcurrentRequests bool
+
+	// MaxDecoderHeaderTableSize optionally specifies an upper limit for the
+	// size of the header compression table used for decoding headers sent
+	// by the peer.
+	// A valid value is less than 4MiB.
+	// If zero or invalid, a default value is used.
+	MaxDecoderHeaderTableSize int
+
+	// MaxEncoderHeaderTableSize optionally specifies an upper limit for the
+	// header compression table used for sending headers to the peer.
+	// A valid value is less than 4MiB.
+	// If zero or invalid, a default value is used.
+	MaxEncoderHeaderTableSize int
+
+	// MaxReadFrameSize optionally specifies the largest frame
+	// this endpoint is willing to read.
+	// A valid value is between 16KiB and 16MiB, inclusive.
+	// If zero or invalid, a default value is used.
+	MaxReadFrameSize int
+
+	// MaxReceiveBufferPerConnection is the maximum size of the
+	// flow control window for data received on a connection.
+	// A valid value is at least 64KiB and less than 4MiB.
+	// If invalid, a default value is used.
+	MaxReceiveBufferPerConnection int
+
+	// MaxReceiveBufferPerStream is the maximum size of
+	// the flow control window for data received on a stream (request).
+	// A valid value is less than 4MiB.
+	// If zero or invalid, a default value is used.
+	MaxReceiveBufferPerStream int
+
+	// SendPingTimeout is the timeout after which a health check using a ping
+	// frame will be carried out if no frame is received on a connection.
+	// If zero, no health check is performed.
+	SendPingTimeout time.Duration
+
+	// PingTimeout is the timeout after which a connection will be closed
+	// if a response to a ping is not received.
+	// If zero, a default of 15 seconds is used.
+	PingTimeout time.Duration
+
+	// WriteByteTimeout is the timeout after which a connection will be
+	// closed if no data can be written to it. The timeout begins when data is
+	// available to write, and is extended whenever any bytes are written.
+	WriteByteTimeout time.Duration
+
+	// PermitProhibitedCipherSuites, if true, permits the use of
+	// cipher suites prohibited by the HTTP/2 spec.
+	PermitProhibitedCipherSuites bool
+
+	// CountError, if non-nil, is called on HTTP/2 errors.
+	// It is intended to increment a metric for monitoring.
+	// The errType contains only lowercase letters, digits, and underscores
+	// (a-z, 0-9, _).
+	CountError func(errType string)
+}