fix: close child stdout pipes on restart and loop convergence (PRD 0043)

Closes #140. In restart_daemon, the old process's stdout pipe was never
explicitly closed after p.wait() returned, leaking the fd until the
supervisor object was GC'd. Similarly, when the watch loop converged
(all children dead), no pipe was closed. Both paths now call
p.stdout.close() immediately after the process is confirmed exited.
Tests enforce this with warnings.simplefilter("error", ResourceWarning)
in TestSupervisor.setUp.

bot_bottle/sidecar_init.py

@@ -245,7 +245,12 @@ class _Supervisor:
                             except ProcessLookupError:
                                 pass
 
-        return all(p.poll() is not None for _, p in self.procs)
+        done = all(p.poll() is not None for _, p in self.procs)
+        if done:
+            for _, p in self.procs:
+                if p.stdout is not None:
+                    p.stdout.close()
+        return done
 
     def exit_code(self) -> int:
         """Positive child failures win; otherwise report success.
@@ -335,6 +340,8 @@ class _Supervisor:
                     except ProcessLookupError:
                         pass
                     p.wait()
+            if p.stdout is not None:
+                p.stdout.close()
             self._logged_dead.discard(daemon_name)
             new_proc = _spawn(spec)
             self.procs[idx] = (spec, new_proc)

tests/unit/test_sidecar_init.py

@@ -14,6 +14,7 @@ import subprocess
 import sys
 import time
 import unittest
+import warnings
 from pathlib import Path
 from unittest.mock import patch
 
@@ -135,6 +136,10 @@ class TestSupervisor(unittest.TestCase):
     We don't go through `main()` because main installs signal
     handlers process-wide, which collides with the test runner."""
 
+    def setUp(self):
+        warnings.simplefilter("error", ResourceWarning)
+        self.addCleanup(warnings.resetwarnings)
+
     def _drive(self, sup: _Supervisor, max_wait_s: float = 6.0) -> int:
         deadline = time.monotonic() + max_wait_s
         while not sup.tick():