fix(module_host): grant Landlock access to IPC socket path

Out-of-process modules timed out with "did not report ready within 45s"
because apply_sandbox never allowed the child to reach breadd's Unix
socket. Path-based AF_UNIX connect is mediated as filesystem access, so
without a rule for the socket (and its parent) UnixStream::connect failed
with EACCES and the hello handshake never completed.

Pass socket_path into apply_sandbox and add baseline ReadDir/ReadFile
rules for the socket directory and path, matching the existing module-
directory grant. Update unit-test call sites accordingly.

graphify-out/cache/last_query_stamp

@@ -0,0 +1 @@
+1785892770.494006