feat(identity): rename user-visible identity to voculinux with one-time legacy import

The fork takes its own name everywhere a user can see it: binaries
(voculinux, voculinux-gui), desktop entry, autostart, tray, D-Bus
namespace (com.voculinux.Voculinux, no alias for the old name),
config/data/cache dirs, single-instance lock, IBus engine identity,
tray icons, resource prefixes, VOCULINUX_* environment names, and the
update-checker user agent. The internal Python module stays vocalinux
and the distribution metadata keeps the upstream URLs as provenance.

On first run a previous Vocalinux install's config.json, custom
dictionary, and portal restore token are copied once into the new
locations (new config always wins, no merge, no write-back); models
re-resolve through the pinned-checksum download path. An offline
naming-sweep test proves no old-name strings remain on user-visible
surfaces outside the allowlist.

Refs #18

tests/conftest.py

@@ -19,11 +19,11 @@ import pytest
 os.environ["PYTEST_RUNNING"] = "1"
 
 # Isolate the whole test process from the developer's real desktop session
-# and Vocalinux state, mirroring a fresh CI runner:
+# and Voculinux state, mirroring a fresh CI runner:
 #   * XDG base dirs point at a throwaway directory, so locally downloaded
-#     models (~/.local/share/vocalinux/models) and the real config file
+#     models (~/.local/share/voculinux/models) and the real config file
 #     never leak into tests. This must happen at conftest import time:
-#     vocalinux modules freeze paths like MODELS_DIR at first import during
+#     voculinux modules freeze paths like MODELS_DIR at first import during
 #     collection, before any fixture could run. The directory is shared for
 #     the whole session on purpose — some tests rely on directories that
 #     earlier tests created, exactly as they do on CI with the runner's HOME.
@@ -31,7 +31,7 @@ os.environ["PYTEST_RUNNING"] = "1"
 #     session flips IBus/keyboard code paths (issue #478) that CI never sees.
 # Tests that need specific values set them via patch.dict/monkeypatch, which
 # layer on top of this.
-_XDG_ISOLATION_DIR = tempfile.mkdtemp(prefix="vocalinux-pytest-xdg-")
+_XDG_ISOLATION_DIR = tempfile.mkdtemp(prefix="voculinux-pytest-xdg-")
 os.environ["XDG_DATA_HOME"] = os.path.join(_XDG_ISOLATION_DIR, "data")
 os.environ["XDG_CONFIG_HOME"] = os.path.join(_XDG_ISOLATION_DIR, "config")
 os.environ["XDG_CACHE_HOME"] = os.path.join(_XDG_ISOLATION_DIR, "cache")
@@ -53,7 +53,7 @@ try:
 except ImportError:
     _real_numpy = None
 else:
-    sys._vocalinux_real_numpy = _real_numpy
+    sys._voculinux_real_numpy = _real_numpy
 
 # And the same for zipfile: test_recognition_manager.py and
 # test_recognition_manager_download_buffer.py assign a MagicMock to
@@ -62,7 +62,7 @@ else:
 # reachable for the ones that need it.
 import zipfile as _real_zipfile  # noqa: E402
 
-sys._vocalinux_real_zipfile = _real_zipfile
+sys._voculinux_real_zipfile = _real_zipfile
 
 # Prevent specific known-blocking daemon threads from starting during tests.
 # Source code in ibus_engine.py and evdev_backend.py spawns daemon threads
@@ -105,7 +105,7 @@ sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")
 
 # Always mock GI/GTK modules before any test files are collected.
 # On CI, real gi (PyGObject) is installed via "pip install PyGObject" and
-# module-level imports in vocalinux source files (ibus_engine, tray_indicator,
+# module-level imports in voculinux source files (ibus_engine, tray_indicator,
 # settings_dialog, etc.) will trigger GTK initialization or IBus daemon
 # connections that hang indefinitely in headless environments.
 # pytest-timeout cannot interrupt these C-level blocking calls.