chore: import vocalinux project

Import the vocalinux source tree (tray app, Next.js site in web/,
packaging, installers, docs and tests) on top of the Gitea template
commit. The project README replaces the template README, and the
template CI files (.gitea/workflows/ci.yml, .jscpd.json, CI.md) are kept.

tests/test_engine_availability.py

@@ -0,0 +1,43 @@
+"""Tests for optional speech-engine availability checks."""
+
+import sys
+import unittest
+from importlib.machinery import ModuleSpec
+from unittest.mock import patch
+
+from vocalinux.speech_recognition import engines
+
+
+class TestEngineAvailability(unittest.TestCase):
+    def test_module_specs_control_availability_without_importing(self) -> None:
+        module_names = ("vosk", "whisper", "faster_whisper")
+        for available_modules in (set(module_names), set()):
+            with self.subTest(available_modules=available_modules):
+                with patch.dict(sys.modules):
+                    for module_name in module_names:
+                        sys.modules.pop(module_name, None)
+
+                    def find_spec(name: str) -> ModuleSpec | None:
+                        if name in available_modules:
+                            return ModuleSpec(name, loader=None)
+                        return None
+
+                    with patch.object(
+                        engines.importlib.util,
+                        "find_spec",
+                        side_effect=find_spec,
+                    ):
+                        available = engines.available_engines()
+
+                    for module_name in module_names:
+                        self.assertEqual(
+                            module_name in available,
+                            module_name in available_modules,
+                        )
+                        self.assertNotIn(module_name, sys.modules)
+
+    def test_module_availability_handles_spec_errors(self) -> None:
+        for error in (ImportError, ValueError):
+            with self.subTest(error=error):
+                with patch.object(engines.importlib.util, "find_spec", side_effect=error):
+                    self.assertFalse(engines._module_available("missing"))