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

install.d/models.sh

@@ -191,7 +191,7 @@ install_whisper_model() {
     print_info "Downloading Whisper tiny model..."
     print_info "This may take a few minutes depending on your internet connection."
 
-    local TEMP_FILE="$VOCALINUX_TMP_DIR/tiny.pt"
+    local TEMP_FILE="$VOCULINUX_TMP_DIR/tiny.pt"
 
     if ! download_model_file "$TINY_MODEL_URL" "$TEMP_FILE" "Whisper model"; then
         return 1
@@ -214,7 +214,7 @@ install_whisper_model() {
         print_success "Whisper tiny model installed successfully ($MODEL_SIZE)"
 
         # Create a marker file to indicate this model was pre-installed
-        echo "$(date)" > "$WHISPER_DIR/.vocalinux_preinstalled"
+        echo "$(date)" > "$WHISPER_DIR/.voculinux_preinstalled"
 
         return 0
     else
@@ -241,7 +241,7 @@ install_vosk_models() {
     # is deleted after unpacking. So whoever unpacks it records the verified zip
     # digest in a stamp (here, and in the app's own downloader), and the directory
     # is trusted only while that stamp matches what we pin today.
-    local SMALL_MODEL_STAMP="$SMALL_MODEL_PATH/.vocalinux_verified"
+    local SMALL_MODEL_STAMP="$SMALL_MODEL_PATH/.voculinux_verified"
     local EXPECTED_ZIP_DIGEST
     EXPECTED_ZIP_DIGEST=$(pinned_digest_for "$SMALL_MODEL_ARCHIVE" || true)
     if [ -d "$SMALL_MODEL_PATH" ]; then
@@ -282,7 +282,7 @@ install_vosk_models() {
     print_info "Downloading small VOSK model (approximately 40MB)..."
     print_info "This may take a few minutes depending on your internet connection."
 
-    local TEMP_ZIP="$VOCALINUX_TMP_DIR/$(basename $SMALL_MODEL_URL)"
+    local TEMP_ZIP="$VOCULINUX_TMP_DIR/$(basename $SMALL_MODEL_URL)"
 
     if ! download_model_file "$SMALL_MODEL_URL" "$TEMP_ZIP" "VOSK model"; then
         return 1
@@ -334,13 +334,13 @@ install_vosk_models() {
     fi
 
     chmod -R 755 "$STAGING_DIR/$SMALL_MODEL_NAME"
-    echo "$(date)" > "$STAGING_DIR/$SMALL_MODEL_NAME/.vocalinux_preinstalled"
+    echo "$(date)" > "$STAGING_DIR/$SMALL_MODEL_NAME/.voculinux_preinstalled"
 
     # Record the digest this tree was extracted from, so a later run can tell a
     # verified model from one that merely exists. Written before the swap: an
     # unstamped tree is one this function would download all over again.
     if [ -z "$EXPECTED_ZIP_DIGEST" ] ||
-       ! printf '%s\n' "$EXPECTED_ZIP_DIGEST" > "$STAGING_DIR/$SMALL_MODEL_NAME/.vocalinux_verified"; then
+       ! printf '%s\n' "$EXPECTED_ZIP_DIGEST" > "$STAGING_DIR/$SMALL_MODEL_NAME/.voculinux_verified"; then
         print_error "Could not record the verified digest for $SMALL_MODEL_NAME"
         rm -rf "$STAGING_DIR"
         return 1
@@ -418,7 +418,7 @@ install_whispercpp_model() {
     print_info "Downloading whisper.cpp tiny model..."
     print_info "This may take a few minutes depending on your internet connection."
 
-    local TEMP_FILE="$VOCALINUX_TMP_DIR/ggml-tiny.bin"
+    local TEMP_FILE="$VOCULINUX_TMP_DIR/ggml-tiny.bin"
 
     if ! download_model_file "$TINY_MODEL_URL" "$TEMP_FILE" "whisper.cpp model"; then
         return 1
@@ -441,7 +441,7 @@ install_whispercpp_model() {
         print_success "whisper.cpp tiny model installed successfully ($MODEL_SIZE)"
 
         # Create a marker file to indicate this model was pre-installed
-        echo "$(date)" > "$WHISPERCPP_DIR/.vocalinux_preinstalled"
+        echo "$(date)" > "$WHISPERCPP_DIR/.voculinux_preinstalled"
 
         return 0
     else