Switch dart-lang/http to use workspaces

[brianquinlan]

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[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:cronet_http	1.6.0-wip	WIP (no publish necessary)
package:cupertino_http	2.4.0-wip	WIP (no publish necessary)
package:http	1.6.0-wip	WIP (no publish necessary)
package:http2	3.0.0	ready to publish	http2-v3.0.0
package:http_multi_server	3.2.2	already published at pub.dev
package:http_parser	4.1.2	already published at pub.dev
package:http_profile	0.1.2-wip	WIP (no publish necessary)
package:ok_http	0.1.1-wip	WIP (no publish necessary)
package:web_socket	1.1.0-wip	WIP (no publish necessary)
package:web_socket_channel	3.1.0-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[github-actions]

PR Health

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

Coverage ✔️

File	Coverage

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License Headers ✔️

// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

Files
no missing headers

All source files should start with a license header.

Unrelated files missing license headers

Files
pkgs/http/example/main.dart