refactor(monitoring): N2 - tach monitoring_tab.py, CanonicalAuditLogger, MonitoringQueryService, go circular import, sandbox matrix

- ui/monitoring_tab.py (1546 dong) tach thanh presentation/monitoring/**
  (container + 7 tab/card + shared helper), ui/monitoring_tab.py con lai
  re-export shim de app.py khong doi.
- infrastructure/telemetry/audit_logger.py: CanonicalAuditLogger, core/audit_log.py
  thanh wrapper mong, tuong thich nguoc 100% voi schema .jsonl cu.
- application/monitoring/monitoring_query_service.py: MonitoringQueryService
  read-only, filter/sort/pagination, khong import PySide6.
- Go circular import model_pricing<->usage_tracker va agent_security<->
  agent_security_alert (core/agent_security_types.py moi).
- infrastructure/sandbox/sandbox_capabilities.py: SandboxCapabilityMatrix
  theo OS (Windows/Linux/macOS), chua dau noi vao core/sandbox_manager.py.
- conftest.py: sua loi checkout khong ten cowork_local khien pytest import
  nham thu muc khac.
- 77 test moi, 167/167 pass. QA da xac nhan UI/business logic khong doi
  (xem evidence/report/unified_report.html).

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

presentation/monitoring/shared/layout_helpers.py

@@ -0,0 +1,27 @@
+"""``kv_row`` — the "label — stretch — value" row shape that
+``ui/monitoring_tab.py`` used to redefine as 3 byte-identical local closures
+(Sandbox Details' ``_kv``, Permissions' ``_pkv``, the detail panel's
+``_field``). Overview's Resource Usage row (``_pair``) is a genuinely
+different layout (inline on one horizontal line with "·" separators, no
+stretch) and is intentionally NOT folded into this helper — unifying it would
+risk a visible layout change.
+"""
+from __future__ import annotations
+
+from typing import Tuple
+
+from PySide6.QtWidgets import QHBoxLayout, QLabel, QVBoxLayout
+
+
+def kv_row(outer_layout: QVBoxLayout, hint_object_name: str = "hint") -> Tuple[QLabel, QLabel]:
+    """Appends a new ``label — stretch — value`` row to ``outer_layout``.
+    Returns ``(label, value)``."""
+    row = QHBoxLayout()
+    label = QLabel()
+    label.setObjectName(hint_object_name)
+    value = QLabel()
+    row.addWidget(label)
+    row.addStretch(1)
+    row.addWidget(value)
+    outer_layout.addLayout(row)
+    return label, value