Add Windows support

Windows joins the three systems as its own entry in each table: DirectShow
through ffmpeg for capture, the Win32 clipboard and SendInput for the paste,
RegisterHotKey for the global shortcut, and the whisper.cpp and llama.cpp
Windows zips (the OpenBLAS whisper build, which transcribes about twice as
fast on a plain CPU). Settings go to APPDATA, data to LOCALAPPDATA, and
install.ps1 adds the Start Menu entry, the dikte command and an optional
autostart. Meetings are not supported yet: Windows offers nothing to record
the far side from.

Porting surfaced three fixes that were not Windows specific:

- A stopped or overlong download tried to delete its .part file while still
  holding it open, which Windows refuses. The unlinks now wait for the handle.
- The CLI transcribed files without handing the local servers their settings
  first, so a local provider failed with "no model downloaded" wherever the
  GUI had not run in the same process.
- The audio content types are pinned instead of asked of the registry, which
  answers differently machine to machine.

One fix is Windows specific but sits in shared code: shutdown() does not end
a blocked recv there, so stopping a request also closes the socket handle.

Co-Authored-By: Claude Fable 5 <[email protected]>

tests/test_audio.py

@@ -606,5 +606,83 @@ class MacRecordingCommand(OnMacOS, DikteTest):
         self.assertFalse(recorder.active)
 
 
+class OnWindows:
+    """A test that runs as if the machine ran Windows."""
+
+    def setUp(self):
+        super().setUp()
+        self.enterContext(mock.patch.object(sys, "platform", "win32"))
+
+
+class WindowsDevices(OnWindows, DikteTest):
+    """The one ffmpeg listing the device questions are answered from.
+
+    dshow names devices rather than numbering them, and the names carry
+    whatever alphabet the machine speaks, so the listing here does too.
+    """
+
+    LISTING = (
+        '[dshow @ 0000020c] "Integrated Camera" (video)\n'
+        '[dshow @ 0000020c]   Alternative name "@device_pnp_\\...."\n'
+        '[dshow @ 0000020c] "Mikrofon Dizisi (Intel Smart Sound)" (audio)\n'
+        '[dshow @ 0000020c]   Alternative name "@device_cm_{33D9A762}...."\n'
+        '[dshow @ 0000020c] "Kulaklık (Soundcore Life Q30)" (audio)\n'
+        "dummy: Immediate exit requested\n"
+    ).encode("utf-8")
+
+    @contextlib.contextmanager
+    def listing(self, stderr=None, tools=("ffmpeg",)):
+        completed = FakeCompleted(
+            returncode=1, stderr=self.LISTING if stderr is None else stderr)
+        with only_these_tools(*tools), \
+                mock.patch.object(subprocess, "run", return_value=completed):
+            yield
+
+    def test_windows_records_through_dshow(self):
+        self.assertIs(audio.sound(), audio.DSHOW)
+
+    def test_the_audio_lines_are_the_only_ones_read(self):
+        with self.listing():
+            self.assertEqual(audio.list_sources(), [
+                ("Mikrofon Dizisi (Intel Smart Sound)",
+                 "Mikrofon Dizisi (Intel Smart Sound)"),
+                ("Kulaklık (Soundcore Life Q30)",
+                 "Kulaklık (Soundcore Life Q30)"),
+            ])
+
+    def test_no_ffmpeg_installed(self):
+        with only_these_tools():
+            self.assertEqual(audio.list_sources(), [])
+            self.assertEqual(audio.recording_command(), [])
+
+    def test_the_name_is_what_the_recorder_is_given_back(self):
+        with self.listing():
+            cmd = audio.recording_command("Kulaklık (Soundcore Life Q30)")
+        self.assertEqual(cmd[cmd.index("-f") + 1], "dshow")
+        self.assertIn("audio=Kulaklık (Soundcore Life Q30)", cmd)
+
+    def test_no_microphone_named_means_the_first_one_listed(self):
+        """dshow has no default device for an empty target to mean."""
+        with self.listing():
+            self.assertIn("audio=Mikrofon Dizisi (Intel Smart Sound)",
+                          audio.recording_command())
+
+    def test_a_machine_with_no_microphone_at_all(self):
+        with self.listing(stderr=b'[dshow @ 0] "Integrated Camera" (video)\n'):
+            self.assertEqual(audio.recording_command(), [])
+
+    def test_an_ffmpeg_that_will_not_run(self):
+        with only_these_tools("ffmpeg"), \
+                mock.patch.object(subprocess, "run", side_effect=OSError("nope")):
+            self.assertEqual(audio.list_sources(), [])
+
+    def test_nothing_offers_the_far_side_of_a_meeting(self):
+        """What the speakers play is not a capture device Windows hands out."""
+        with self.listing():
+            self.assertEqual(audio.list_monitors(), [])
+            self.assertEqual(audio.default_monitor(), "")
+            self.assertEqual(audio.meeting_command("mic", "sys"), [])
+
+
 if __name__ == "__main__":
     unittest.main()