Add Remote session foundations and feasibility checks

Add opt-in Tentacle protocol 1.1, explicit remote grants, lifecycle IPC and expiring core leases in both SDKs. Revoke access before update preparation, including failed updates.

Add transient secret entries, shared Braille cell export and isolated Xorg recovery experiments with focused tests and documented limitations. Production consent, desktop services and live interoperability remain pending.

internal/tentacle/testdata/sdk_peer.py

@@ -38,4 +38,15 @@ if pathlib.Path(sys.argv[1]).name == "presentation":
     commands.append(Command("present", "Present", "",
         lambda cancelled, arguments: present(speech="Hello, é猫😀é", braille="Display é猫😀é", uninterruptible=True),
         presentation=True))
+if pathlib.Path(sys.argv[1]).name == "secret":
+    commands.extend([
+        Command("secret", "Secret", "", lambda cancelled, arguments: {
+            "form": {"title": "Connection", "elements": [
+                {"id": "key", "label": "Channel key", "kind": 2,
+                 "secret": True, "required": True}]}, "next": "submit"},
+            presentation=True, interaction=True),
+        Command("submit", "Submit", "", lambda cancelled, arguments:
+            arguments["values"]["key"]["text"] == "fixture猫",
+            presentation=True, interaction=True),
+    ])
 serve(commands)

internal/tentacle/testdata/session_peer.py

@@ -0,0 +1,33 @@
+# Copyright (c) 2026 Storm Dragon
+# SPDX-License-Identifier: GPL-3.0-or-later
+import pathlib
+import sys
+
+sys.path.insert(0, str(pathlib.Path(__file__).resolve().parents[3] / 'sdk' / 'python'))
+from cthulhu_tentacle import Command, SessionClient, SessionError, serve
+
+client = SessionClient()
+
+
+def request(cancelled, arguments):
+    try:
+        return {'value': client.call(arguments['method'], arguments['params'])}
+    except SessionError as error:
+        return {'code': error.code}
+
+
+def event(cancelled, arguments):
+    return client.next_event()
+
+
+def wait(cancelled, arguments):
+    cancelled.wait()
+    return None
+
+
+try:
+    serve([Command('request', 'Request', '', request), Command('event', 'Event', '', event),
+           Command('wait', 'Wait', '', wait),
+           Command('large', 'Large', '', lambda cancelled, args: 'x' * (48 * 1024))], session_client=client)
+except Exception:
+    sys.exit(1)