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]>

i18n.py

@@ -106,6 +106,10 @@ TR = {
         "Ses kayıt aracı bulunamadı. pulseaudio-utils ya da pipewire-audio kur.",
     "ffmpeg not found. Install it with: brew install ffmpeg":
         "ffmpeg bulunamadı. Şununla kur: brew install ffmpeg",
+    "ffmpeg or a microphone was not found. Install ffmpeg with: "
+    "winget install Gyan.FFmpeg":
+        "ffmpeg ya da bir mikrofon bulunamadı. ffmpeg'i şununla kur: "
+        "winget install Gyan.FFmpeg",
     "Audio recorder stopped before receiving sound: {error}":
         "Ses kayıt aracı veri alamadan kapandı: {error}",
     "Could not copy to clipboard: {error}": "Panoya kopyalanamadı: {error}",
@@ -355,6 +359,12 @@ TR = {
     "macOS would not give Dikte {shortcut}; another application already holds it.":
         "macOS {shortcut} kombinasyonunu Dikte'ye vermedi; başka bir uygulama "
         "onu şimdiden tutuyor.",
+    "Could not reach the Windows shortcut service: {error}":
+        "Windows kısayol servisine ulaşılamadı: {error}",
+    "Windows would not give Dikte {shortcut}; another application already "
+    "holds it.":
+        "Windows {shortcut} kombinasyonunu Dikte'ye vermedi; başka bir uygulama "
+        "onu şimdiden tutuyor.",
     "Cannot read /dev/input. Your user needs to be in the 'input' group:\n"
     "  sudo usermod -aG input $USER   (then log out and back in)":
         "/dev/input okunamıyor. Kullanıcının 'input' grubunda olması gerekir:\n"