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]>

audio.py

@@ -30,6 +30,10 @@ from PyQt6.QtCore import QObject, pyqtSignal
 
 from i18n import t
 
+# Console programs started from a windowless process would otherwise each open
+# a console window of their own on Windows.
+NO_WINDOW = getattr(subprocess, "CREATE_NO_WINDOW", 0) if sys.platform == "win32" else 0
+
 RATE = 16000
 CHANNELS = 1
 SAMPLE_WIDTH = 2  # s16
@@ -39,6 +43,19 @@ CHUNK_LATENCY_MS = round(CHUNK_FRAMES / RATE * 1000)
 MIN_FRAMES = int(RATE * 0.25)
 
 
+def _interrupt(proc):
+    """Ask a recorder process to end.
+
+    SIGINT is the polite way everywhere it exists; Windows has no equivalent a
+    child can be sent, so the process is terminated outright. The captured
+    audio is not lost either way: it has already been read from the pipe.
+    """
+    if sys.platform == "win32":
+        proc.terminate()
+    else:
+        proc.send_signal(signal.SIGINT)
+
+
 class Recorder(QObject):
     """Runs the available sound-server recorder and reads raw PCM from stdout."""
 
@@ -70,7 +87,8 @@ class Recorder(QObject):
 
         try:
             self._proc = subprocess.Popen(
-                cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=0
+                cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, bufsize=0,
+                creationflags=NO_WINDOW,
             )
         except OSError as exc:
             self.failed.emit(t("Could not start recording: {error}", error=exc))
@@ -125,7 +143,7 @@ class Recorder(QObject):
         proc = self._proc
         if proc and proc.poll() is None:
             try:
-                proc.send_signal(signal.SIGINT)
+                _interrupt(proc)
                 proc.wait(timeout=1.5)
             except (subprocess.TimeoutExpired, OSError):
                 try:
@@ -246,7 +264,8 @@ class MeetingRecorder(QObject):
             # nobody drains would eventually block it, so it writes to a file.
             self._log = tempfile.TemporaryFile()
             self._proc = subprocess.Popen(
-                cmd, stdout=subprocess.PIPE, stderr=self._log, bufsize=0
+                cmd, stdout=subprocess.PIPE, stderr=self._log, bufsize=0,
+                creationflags=NO_WINDOW,
             )
         except (OSError, wave.Error) as exc:
             self._close_file()
@@ -298,7 +317,7 @@ class MeetingRecorder(QObject):
         proc = self._proc
         if proc and proc.poll() is None:
             try:
-                proc.send_signal(signal.SIGINT)
+                _interrupt(proc)
                 proc.wait(timeout=2)
             except (subprocess.TimeoutExpired, OSError):
                 try:
@@ -603,6 +622,71 @@ def _avfoundation_default_output():
     return ""
 
 
+# Windows records through DirectShow, the one capture API ffmpeg's Windows
+# builds all ship with. What the speakers are playing is not offered as a
+# device at all, so a meeting has nothing to record the far side from yet.
+
+
+def _dshow_devices():
+    """[(name, name)] for every DirectShow audio capture device.
+
+    The list comes out on stderr of a command that then fails, the same
+    documented trick AVFoundation uses above. Names are the only stable handle
+    dshow offers a user; they are what the recorder is given back.
+    """
+    if not shutil.which("ffmpeg"):
+        return []
+    try:
+        result = subprocess.run(
+            ["ffmpeg", "-hide_banner", "-list_devices", "true",
+             "-f", "dshow", "-i", "dummy"],
+            capture_output=True, timeout=8, check=False, creationflags=NO_WINDOW,
+        )
+    except (subprocess.SubprocessError, OSError):
+        return []
+
+    devices = []
+    for line in result.stderr.decode("utf-8", "replace").splitlines():
+        if "(audio)" not in line:
+            continue
+        match = re.search(r'"([^"]+)"\s*\([^)]*audio[^)]*\)', line)
+        if match:
+            devices.append((match.group(1), match.group(1)))
+    return devices
+
+
+def _dshow_record(target):
+    if not shutil.which("ffmpeg"):
+        return []
+    # dshow has no "default" device: an unset target means the first one listed.
+    device = target
+    if not device:
+        inputs = _dshow_devices()
+        if not inputs:
+            return []
+        device = inputs[0][0]
+    return [
+        "ffmpeg", "-hide_banner", "-nostdin", "-loglevel", "error",
+        # dshow holds half a second of audio before handing anything over;
+        # asked for the chunk the level meter is measured in instead.
+        "-f", "dshow", "-audio_buffer_size", str(CHUNK_LATENCY_MS),
+        "-i", f"audio={device}",
+        "-ac", str(CHANNELS), "-ar", str(RATE), "-f", "s16le", "-",
+    ]
+
+
+def _dshow_meeting(mic_target, system_target):
+    return []  # no monitor devices to record the far side from
+
+
+def _dshow_no_outputs():
+    return []
+
+
+def _dshow_no_default_output():
+    return ""
+
+
 Sound = collections.namedtuple(
     "Sound",
     # How to capture one source and two at once, the two device lists, which
@@ -633,9 +717,24 @@ COREAUDIO = Sound(
 )
 
 
+DSHOW = Sound(
+    record=_dshow_record,
+    meeting=_dshow_meeting,
+    inputs=_dshow_devices,
+    outputs=_dshow_no_outputs,
+    default_output=_dshow_no_default_output,
+    missing="ffmpeg or a microphone was not found. Install ffmpeg with: "
+            "winget install Gyan.FFmpeg",
+)
+
+
 def sound():
     """The programs this machine records through."""
-    return COREAUDIO if sys.platform == "darwin" else PULSE
+    if sys.platform == "darwin":
+        return COREAUDIO
+    if sys.platform == "win32":
+        return DSHOW
+    return PULSE
 
 
 def list_sources():