feat(safety): workspace-file reads, approval UX, and integration hardening

Engine + integration:
- Reviewer inspection now surfaces the real frozen source of an already-frozen
  workspace script/dependency instead of an empty string, so workspace-resident
  scripts resolve without a needless human defer.
- Guard effectful static tools via an explicit, documented set plus the SDK's
  per-tool needs_approval signal; give the exec/stdin wrappers the same
  idempotency guard as their sibling wrappers.
- Centralize DEFAULT_SAFETY_MODE and share one resume safety-mode rule between the
  CLI and runner so the two cannot drift; type InspectionContext.runner, reuse
  RUNTIME_STATE_DIR_NAME, and drop a dead workdir parameter and a write-only field.

TUI approval experience:
- Approve All drops the run into dangerous mode: it approves the pending call and
  turns review off for the rest of the run, with a standing "review off" status flag.
- The status row shows the owning agent as paused while it waits on a decision.
- Redesigned prompt: a risk + tool header, a collapsible command/reason preview
  that expands (e) and scrolls, and no internal digest, agent, or request ids.

Full Python (1138) and Go suites, ruff, and mypy strix/ pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_tui_backend_server.py

@@ -115,6 +115,32 @@ async def receive_initial_state(connection: socket.socket) -> None:
                 complete.add(payload["collection"])
 
 
+@pytest.mark.asyncio
+async def test_state_frame_can_carry_many_concurrent_approvals() -> None:
+    controller = TuiController(args())
+    requests = [
+        asyncio.create_task(
+            controller.safety_approval_callback(
+                {
+                    "request_id": f"approval-{index}",
+                    "agent_id": f"agent-{index}",
+                    "action": "x" * 500,
+                    "reason": "y" * 500,
+                }
+            )
+        )
+        for index in range(80)
+    ]
+    await asyncio.sleep(0)
+    server = TuiBackendServer(controller)
+
+    encoded = server._encode(envelope("state", {"revision": 1, "state": controller.snapshot()}))
+
+    assert len(encoded) > MAX_COMMAND_BYTES
+    await controller.cancel_pending_safety_approvals()
+    assert set(await asyncio.gather(*requests)) == {"cancelled"}
+
+
 @pytest.mark.asyncio
 async def test_server_requires_ready_before_state_or_commands() -> None:
     backend, child = socket.socketpair()