Add community node socket: devices, tickets, consent gate, kill switch

Phase 3 of plan.md. Device registration with one-time secrets, scoped single-use
socket tickets, the lock-owner WS /nodes/ws with handshake and heartbeat eviction,
a single batch ConsentGate, and NodesService which disconnects nodes within one tick
when consent, device or the nodes_enabled kill switch changes. A reconcile of 2000
sessions measured about 110 ms after replacing per-session queries with batches.
Devii may withdraw but never grant bandwidth_sharing.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

devplacepy/database/nodes.py

@@ -12,7 +12,7 @@ from sqlalchemy import text
 from devplacepy.config import SECRET_KEY
 from devplacepy.services.nodes.spec import DEVICE_KINDS, SPEC
 
-from .core import _now_iso, db, get_table
+from .core import _in_clause, _now_iso, db, get_table
 from .soft_delete import soft_delete
 
 LIMITS = SPEC.limits
@@ -23,6 +23,7 @@ SECRET_BYTES = 32
 LABEL_MAX = 60
 EVENT_DETAIL_MAX = 500
 MEGABYTE = 1024 * 1024
+BATCH_SIZE = 500
 HOURS_PATTERN = re.compile(r"^([01]\d|2[0-3]):[0-5]\d$")
 PLATFORMS = tuple(sorted({item.adapter for item in SPEC.destinations}))
 FLAG_OPEN = "open"
@@ -125,6 +126,37 @@ def get_device(device_uid: str) -> dict | None:
     return get_table("node_devices").find_one(uid=device_uid, deleted_at=None)
 
 
+def _batches(values) -> list[list[str]]:
+    unique = list(dict.fromkeys(value for value in values if value))
+    return [unique[i : i + BATCH_SIZE] for i in range(0, len(unique), BATCH_SIZE)]
+
+
+def get_devices_by_uids(device_uids) -> dict[str, dict]:
+    found: dict[str, dict] = {}
+    for batch in _batches(device_uids):
+        placeholders, params = _in_clause(batch)
+        for row in db.query(
+            f"SELECT * FROM node_devices WHERE uid IN ({placeholders}) "
+            "AND deleted_at IS NULL",
+            **params,
+        ):
+            found[row["uid"]] = dict(row)
+    return found
+
+
+def get_enabled_by_users(user_uids) -> dict[str, bool]:
+    found: dict[str, bool] = {}
+    for batch in _batches(user_uids):
+        placeholders, params = _in_clause(batch)
+        for row in db.query(
+            f"SELECT user_uid, enabled FROM node_settings WHERE user_uid IN ({placeholders}) "
+            "AND deleted_at IS NULL",
+            **params,
+        ):
+            found[row["user_uid"]] = bool(row["enabled"])
+    return found
+
+
 def list_devices(user_uid: str) -> list[dict]:
     return list(
         get_table("node_devices").find(