Remove http-proxy-node16, replace with lightweight inline proxy

[ryancbahan]

Summary

• Add http-proxy.ts (~100 lines) implementing web() and ws() proxy methods using Node's built-in http/https modules
• HTTP forwarding: pipes request to target, pipes response back with headers
• WebSocket forwarding: handles upgrade handshake, bidirectional socket piping, proper error cleanup
• Remove http-proxy-node16 from packages/app/package.json

Tophatting

• confirm shopify app dev still works as expected
• confirm dev console in admin still receives ws updates from cli

[ryancbahan]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Remove is-interactive, inline the TTY check #7198
• Remove http-proxy-node16, replace with lightweight inline proxy #7196 👈 (View in Graphite)
• Remove network-interfaces, use os.networkInterfaces() directly #7195
• Remove camelcase-keys, replace with inline utility #7194
• Remove ansi-colors, replace with lightweight inline utility #7193
• Remove tmp and @types/tmp dependencies #7192
• main

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[github-actions]

We detected some changes at packages/*/src and there are no updates in the .changeset.
If the changes are user-facing, run pnpm changeset add to track your changes and include them in the next release CHANGELOG.

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[gonzaloriestra]

I'm not sure about this change. I agree with replacing simple libraries with our own code, but this looks a bit complex (even if it's small)...

For example, some concerns by Claude that were apparently handled by the library:

1. connection: 'close' on every proxied request — this disables keep-alive, which could add latency for repeated requests to the same backend during app dev. A battle-tested proxy library would handle connection pooling properly.
2. Manual HTTP response construction in WS upgrade — writing raw HTTP/1.1 101 Switching Protocols\r\n... strings is fragile. Edge cases around header formatting (multi-value headers, encoding) can cause subtle breakage.
3. No timeout handling — if a backend hangs, the proxy request will hang indefinitely.