fix(snap): add hardware-observe so hotkeys can read input devices (#858)

Snap confinement denies /proc/bus/input/devices unless hardware-observe
is connected. Declare the plug, tell users to connect it next to
raw-input, and update the in-app hints.

Fixes #857

tests/test_evdev_backend_ext.py

@@ -394,6 +394,32 @@ class TestEvdevKeyboardBackendPermissionHint:
         result = backend.get_permission_hint()
         assert result is None
 
+    @patch.dict("os.environ", {"SNAP": "/snap/vocalinux/x1"}, clear=False)
+    @patch("vocalinux.ui.keyboard_backends.evdev_backend.EVDEV_AVAILABLE", True)
+    @patch("vocalinux.ui.keyboard_backends.evdev_backend.find_keyboard_devices")
+    def test_permission_hint_snap_no_devices(self, mock_find_devices):
+        """Snap with no listed devices should ask for both input plugs."""
+        mock_find_devices.return_value = []
+        backend = EvdevKeyboardBackend()
+        result = backend.get_permission_hint()
+        assert result is not None
+        assert "raw-input" in result
+        assert "hardware-observe" in result
+
+    @patch.dict("os.environ", {"SNAP": "/snap/vocalinux/x1"}, clear=False)
+    @patch("vocalinux.ui.keyboard_backends.evdev_backend.EVDEV_AVAILABLE", True)
+    @patch("vocalinux.ui.keyboard_backends.evdev_backend.find_keyboard_devices")
+    @patch("vocalinux.ui.keyboard_backends.evdev_backend.InputDevice")
+    def test_permission_hint_snap_permission_denied(self, mock_input_device, mock_find_devices):
+        """Snap that cannot open /dev/input should ask for both input plugs."""
+        mock_find_devices.return_value = ["/dev/input/event0"]
+        mock_input_device.side_effect = OSError(errno.EACCES, "Permission denied")
+        backend = EvdevKeyboardBackend()
+        result = backend.get_permission_hint()
+        assert result is not None
+        assert "raw-input" in result
+        assert "hardware-observe" in result
+
 
 class TestEvdevKeyboardBackendStart:
     """Test start() method."""

tests/test_keyboard_shortcuts.py

@@ -354,6 +354,17 @@ class TestKeyboardShortcuts(unittest.TestCase):
             warning_calls = [str(call) for call in mock_logger.warning.call_args_list]
             self.assertTrue(any("Permission issue" in str(call) for call in warning_calls))
 
+    def test_unavailable_hints_snap_lists_both_connects(self):
+        """Snap log banner should list both raw-input and hardware-observe."""
+        self.mock_create_backend.return_value = None
+        with patch.dict("os.environ", {"SNAP": "/snap/vocalinux/x1"}, clear=False):
+            with patch("vocalinux.ui.keyboard_shortcuts.logger") as mock_logger:
+                KeyboardShortcutManager()
+
+        messages = " ".join(str(call) for call in mock_logger.warning.call_args_list)
+        self.assertIn("raw-input", messages)
+        self.assertIn("hardware-observe", messages)
+
 
 class TestPynputBackend(unittest.TestCase):
     """Test cases for the pynput backend specifically."""

tests/test_snap_packaging.py

@@ -24,11 +24,16 @@ def test_snapcraft_recipe_and_gui_assets() -> None:
 
     plugs = set((doc.get("apps") or {}).get("vocalinux", {}).get("plugs") or [])
     assert "raw-input" in plugs
+    assert "hardware-observe" in plugs
     assert "audio-record" in plugs
     assert "uinput" in plugs
     stage = doc["parts"]["vocalinux"].get("stage-packages") or []
     assert "ydotool" in stage
 
+    recipe_text = SNAPCRAFT_YAML.read_text(encoding="utf-8")
+    assert "sudo snap connect vocalinux:raw-input" in recipe_text
+    assert "sudo snap connect vocalinux:hardware-observe" in recipe_text
+
     assert DESKTOP_FILE.is_file()
     assert SNAP_PNG.is_file()
     assert SNAP_PNG.stat().st_size > 0
@@ -50,6 +55,16 @@ def test_snap_puts_gnome_platform_first_on_ld_library_path() -> None:
     assert ld_path.endswith(":$LD_LIBRARY_PATH")
 
 
+def test_snap_docs_tell_users_to_connect_hardware_observe() -> None:
+    """Hotkeys need hardware-observe for /proc/bus/input/devices (#857)."""
+    readme = (REPO_ROOT / "README.md").read_text(encoding="utf-8")
+    install = (REPO_ROOT / "docs" / "INSTALL.md").read_text(encoding="utf-8")
+    snapcraft = SNAPCRAFT_YAML.read_text(encoding="utf-8")
+    for text in (readme, install, snapcraft):
+        assert "sudo snap connect vocalinux:raw-input" in text
+        assert "sudo snap connect vocalinux:hardware-observe" in text
+
+
 def test_snap_docs_warn_that_0162_has_no_uinput_plug() -> None:
     """v0.16.2 edge (rev 7) has no uinput plug; the connect command must not stand alone."""
     readme = (REPO_ROOT / "README.md").read_text(encoding="utf-8")