Add build-mode --socket/--host flags and dedupe dev side-cars

[silviogutierrez]

Build mode serves Django directly, so the dev server's listener is ours to choose. Two flags plus a side-car fix.

--socket

Bind a unix socket instead of TCP. A reverse proxy in front of a preview/staging deploy wants a stable address, but the dev port is allocated per checkout, so the proxy can't know it at config time — today that gap needs a forwarding side-car per deploy. A socket removes the bridge entirely. A crashed run's leftover socket file is cleared once we confirm nothing is accepting on it, and it's unlinked on exit.

--host

Widen the bind past loopback, so the dev server is reachable from another machine without a forwarding side-car. Independent of the socket work.

Both are build-mode only and exit with a clear message otherwise (in vite mode the user-facing listener is Vite's express server, and uvicorn is an implementation detail behind it). --socket + --port is rejected as mutually exclusive. When a socket is bound, DJANGO_PORT is not exported (nothing listens on a port).

Dedupe dev side-cars

parse_processes() collapses duplicate lines in REACTIVATED_DEV_PROCESSES (first wins, order preserved). The variable is exported, so a project's env setup that appends its own lines re-appends them on every nested shell entry — which is why a project ends up clearing the variable, and clearing is what silently drops a side-car an outer caller injected. With dedupe, a project can seed from the inherited value instead.

Tests / verification

• New tests/dev_procs.py: parse_processes (incl. the inherited-line case) and is_socket_serving across absent / stale / live.
• Full server suite: 124 passed, 2 skipped; ruff check + format clean.
• The uds wiring is proven end to end: the same uvicorn Config the CLI now builds bound an AF_UNIX socket (uds wins over host/port), is_socket_serving reported True, and a request over the socket returned HTTP 200.

Pre-merge check worth doing: a full reactivate --build --socket against development/ was not run (that app's node_modules/reactivated isn't linked in a fresh clone, so build.client 404s before the server starts — a pre-existing bootstrap gap, unrelated). The uds mechanism the flag depends on is covered above.

🤖 Generated with Claude Code

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[silviogutierrez]

Superseded by #488, which carries these commits (re-authored so the CLA passes) plus the NewType schema fix. Closing.