fix(runserver): don't capture watch subprocess stdout

Both ProcessManager and MultiWatchProcessManager spawned the Tailwind
CLI watch subprocess with `stdout=PIPE, stderr=STDOUT` but never read
from the pipe — the monitor loop only polls process state. Once the OS
pipe buffer (~64 KB on Linux) fills up, the watcher blocks on its next
write and silently stops rebuilding, which is exactly the symptom you'd
never suspect in a long dev session.

Drop the stdout/stderr overrides (and the now-unnecessary bufsize=1) so
the watch subprocess inherits the parent streams. The watch output now
flows straight to the terminal — a UX improvement on top of the
deadlock fix, because the user can finally see rebuild progress during
`tailwind runserver`.

Author: oliverandrich

src/django_tailwind_cli/management/commands/tailwind.py

@@ -1043,14 +1043,14 @@ def start_concurrent_processes(self, watch_cmd: list[str], server_cmd: list[str]
         signal.signal(signal.SIGTERM, self._signal_handler)
 
         try:
-            # Start Tailwind watch process
+            # Start Tailwind watch process — inherit stdout/stderr so the
+            # user sees watch output live and we avoid a pipe-fill deadlock:
+            # the OS pipe buffer (~64 KB on Linux) would otherwise fill up
+            # after a few minutes of rebuilds and block the watcher.
             watch_process = subprocess.Popen(
                 watch_cmd,
                 cwd=settings.BASE_DIR,
-                stdout=subprocess.PIPE,
-                stderr=subprocess.STDOUT,
                 text=True,
-                bufsize=1,  # Line buffered
             )
             self.processes.append(watch_process)
             typer.secho("Started Tailwind CSS watch process", fg=typer.colors.GREEN)
@@ -1141,13 +1141,13 @@ def start_watch_processes(self, config: Config, *, verbose: bool = False) -> Non
                     typer.secho(f"🚀 Starting watch for '{entry.name}'...", fg=typer.colors.CYAN)
                     typer.secho(f"   • Command: {' '.join(watch_cmd)}", fg=typer.colors.BLUE)
 
+                # Inherit stdout/stderr so output flows to the terminal and we
+                # avoid a pipe-fill deadlock — the OS pipe buffer would otherwise
+                # block the watcher after ~64 KB of rebuild status lines.
                 process = subprocess.Popen(
                     watch_cmd,
                     cwd=settings.BASE_DIR,
-                    stdout=subprocess.PIPE,
-                    stderr=subprocess.STDOUT,
                     text=True,
-                    bufsize=1,
                 )
                 self.processes.append(process)
                 typer.secho(f"Watching '{entry.name}': {entry.src_css}", fg=typer.colors.GREEN)