fix(backup,restore): harden the branch fixes and prove them with tests

Backup: a container that vanishes between the docker ps listing and the
swarm-task inspect (--rm one-shots, task-history GC) no longer aborts the
whole backup run; it counts as not stoppable and is skipped.

Restore: the postgres replay streams the dump through a spooled temp file
instead of buffering it three times in memory (multi-GB dumps OOMed the
restore mid-replay), and the superuser-only line filter is COPY-aware: data
rows inside COPY ... FROM stdin blocks pass through untouched, so a row
that happens to start with COMMENT ON EXTENSION or ALTER DEFAULT PRIVILEGES
is no longer silently dropped.

The e2e runner talks to the DinD daemon through docker exec instead of a
host-published tcp://127.0.0.1:2375: port publishing is unreachable from
sandboxed runners and from hosts with broken loopback publishing, and the
unencrypted root API port disappears from the host. The debug tmp dump
shrinks to tar plus docker cp against the DinD container itself.

New coverage: an e2e reproducing the swarm flake end to end (service task
on the volume, nothing whitelisted: the backup must succeed, the very same
task container must keep running, and the service must never replace a
task), unit tests for the COPY-aware filter, the swarm-task probe including
the vanished-container path, filter_stoppable ordering, and the one-session
FOREIGN_KEY_CHECKS drop assembly. Full suite: 35 unit, 9 integration,
30 e2e green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/baudolo/restore/db/postgres.py

@@ -1,9 +1,41 @@
 from __future__ import annotations
 
 import os
+import tempfile
+from collections.abc import Iterable, Iterator
 
 from ..run import docker_exec
 
+_SUPERUSER_ONLY_PREFIXES = (b"COMMENT ON EXTENSION", b"ALTER DEFAULT PRIVILEGES")
+
+
+def filter_superuser_only_lines(lines: Iterable[bytes]) -> Iterator[bytes]:
+    """Drop superuser-only statements an app-level psql replay cannot run.
+
+    Args:
+        lines: dump lines including their trailing newlines.
+
+    Yields:
+        Every line except top-level statements starting with a superuser-only
+        prefix. Lines inside COPY ... FROM stdin data blocks are passed
+        through untouched: a data row may legally start with the same bytes,
+        and dropping it would silently corrupt the restored table.
+    """
+    in_copy = False
+    for line in lines:
+        if in_copy:
+            yield line
+            if line.rstrip(b"\r\n") == b"\\.":
+                in_copy = False
+            continue
+        if line.startswith(b"COPY ") and line.rstrip(b"\r\n").endswith(b"FROM stdin;"):
+            in_copy = True
+            yield line
+            continue
+        if line.startswith(_SUPERUSER_ONLY_PREFIXES):
+            continue
+        yield line
+
 
 def restore_postgres_sql(
     *,
@@ -68,19 +100,18 @@ END $$;
             docker_env=docker_env,
         )
 
-    with open(sql_path, "rb") as f:
-        raw_sql = f.read()
-    # COMMENT ON EXTENSION and ALTER DEFAULT PRIVILEGES are superuser-only;
-    # app-level restores must skip them or ON_ERROR_STOP aborts the replay.
-    superuser_only = (b"COMMENT ON EXTENSION", b"ALTER DEFAULT PRIVILEGES")
-    sql = b"\n".join(
-        line for line in raw_sql.splitlines() if not line.startswith(superuser_only)
-    )
-    docker_exec(
-        container,
-        ["psql", "-v", "ON_ERROR_STOP=1", "-U", user, "-d", db_name],
-        stdin=sql,
-        docker_env=docker_env,
-    )
+    # Filter into a spooled temp file instead of building the whole dump in
+    # memory: production dumps reach many GB and the previous read/splitlines/
+    # join needed roughly three times the dump size in RSS.
+    with open(sql_path, "rb") as src, tempfile.TemporaryFile() as filtered:
+        for line in filter_superuser_only_lines(src):
+            filtered.write(line)
+        filtered.seek(0)
+        docker_exec(
+            container,
+            ["psql", "-v", "ON_ERROR_STOP=1", "-U", user, "-d", db_name],
+            stdin=filtered,
+            docker_env=docker_env,
+        )
 
     print(f"PostgreSQL restore complete for db '{db_name}'.")