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

docs/TROUBLESHOOTING.md

@@ -5,36 +5,36 @@ Common install and runtime problems. Install overview: [INSTALL.md](INSTALL.md).
 Always try once with debug logs:
 
 ```bash
-vocalinux --debug
+voculinux --debug
 ```
 
-## Command not found: `vocalinux`
+## Command not found: `voculinux`
 
 ```bash
 # Official install wrappers
 export PATH="$HOME/.local/bin:$PATH"
-vocalinux
+voculinux
 
 # Or run the venv binary
-~/.local/share/vocalinux/venv/bin/vocalinux
+~/.local/share/voculinux/venv/bin/voculinux
 
 # Source checkout
 source venv/bin/activate
-vocalinux
+voculinux
 ```
 
 ## No audio / microphone not working
 
 1. Check system sound settings and mute state
 2. List capture devices: `arecord -l`
-3. Run `vocalinux --debug` and confirm the selected device
-4. Reset a bad device index: set `audio.device_index` to `null` in `~/.config/vocalinux/config.json`
+3. Run `voculinux --debug` and confirm the selected device
+4. Reset a bad device index: set `audio.device_index` to `null` in `~/.config/voculinux/config.json`
 5. Bluetooth mics: try a wired device to isolate SCO capture issues
 
 ### Microphone Stalled
 
 A **Microphone Stalled** notification means the selected input stopped delivering
-audio. Vocalinux stops the failed dictation attempt.
+audio. Voculinux stops the failed dictation attempt.
 
 Open **Settings → Audio**. Use **Microphone Test → Test** to record two seconds and
 check the audio level, or select a different **Input Device**, then retry
@@ -75,7 +75,7 @@ Refresh icons:
 
 ```bash
 gtk-update-icon-cache -f -t ~/.local/share/icons/hicolor
-vocalinux --debug
+voculinux --debug
 ```
 
 ## Text not injected into apps
@@ -95,7 +95,7 @@ wtype "hello"
 printf "bonjour" | xsel --clipboard --input
 ```
 
-**KDE Plasma Wayland:** `wtype` may fail if the compositor does not expose a virtual keyboard to normal clients. Prefer **System Settings → Keyboard → Virtual Keyboard → IBus Wayland**, then restart Vocalinux (or log out/in).
+**KDE Plasma Wayland:** `wtype` may fail if the compositor does not expose a virtual keyboard to normal clients. Prefer **System Settings → Keyboard → Virtual Keyboard → IBus Wayland**, then restart Voculinux (or log out/in).
 
 Install IBus if needed:
 
@@ -115,8 +115,8 @@ Compositor-specific notes: [DISTRO_COMPATIBILITY.md](DISTRO_COMPATIBILITY.md).
 Models download on first use. Manual VOSK example:
 
 ```bash
-mkdir -p ~/.local/share/vocalinux/models
-cd ~/.local/share/vocalinux/models
+mkdir -p ~/.local/share/voculinux/models
+cd ~/.local/share/voculinux/models
 wget https://alphacephei.com/vosk/models/vosk-model-small-en-us-0.15.zip
 unzip vosk-model-small-en-us-0.15.zip
 ```
@@ -128,23 +128,23 @@ whisper.cpp models are managed from Settings or first-run download.
 
 ```bash
 # Unresolved libs
-ldd $(find ~/.local/share/vocalinux/venv -name '*.so' -path '*/pywhispercpp*' 2>/dev/null | head -1) | grep 'not found'
+ldd $(find ~/.local/share/voculinux/venv -name '*.so' -path '*/pywhispercpp*' 2>/dev/null | head -1) | grep 'not found'
 
 # Rebuild whisper.cpp bindings via installer
 ./install.sh --auto --rebuild-whispercpp
 
 # Or switch to VOSK temporarily
-vocalinux --engine vosk
+voculinux --engine vosk
 ```
 
 ## Old process still running after update
 
-Stop via the tray, or use the lock-file PID (do **not** use `pkill -f vocalinux`; it can kill editors and shells):
+Stop via the tray, or use the lock-file PID (do **not** use `pkill -f voculinux`; it can kill editors and shells):
 
 ```bash
-kill "$(tr -d '[:space:]' < "${XDG_DATA_HOME:-$HOME/.local/share}/vocalinux/instance.lock")"
-kill "$(tr -d '[:space:]' < "${XDG_DATA_HOME:-$HOME/.local/share}/vocalinux-ibus/engine.pid")"
-vocalinux
+kill "$(tr -d '[:space:]' < "${XDG_DATA_HOME:-$HOME/.local/share}/voculinux/instance.lock")"
+kill "$(tr -d '[:space:]' < "${XDG_DATA_HOME:-$HOME/.local/share}/voculinux-ibus/engine.pid")"
+voculinux
 ```
 
 ## Clean reinstall