DroppedNeedle: pass release version to the app via COMMIT_TAG

The app reads its version from COMMIT_TAG and falls back to "dev".
Set it in the systemd unit on install, migration and update.

Fixes #18040

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ct/droppedneedle.sh

@@ -91,6 +91,7 @@ User=root
 WorkingDirectory=/opt/droppedneedle/backend
 Environment=ROOT_APP_DIR=/opt/droppedneedle/backend
 Environment=PORT=8688
+Environment=COMMIT_TAG=v$(<~/.droppedneedle)
 # Environment=SLSKD_DOWNLOADS_PATH=<path-to-slskd-downloads>
 ExecStart=/opt/droppedneedle/venv/bin/python -m maintenance.automatic_upgrade --start-target
 Restart=on-failure
@@ -106,6 +107,11 @@ EOF
         sed -i '\|=8688$|a# Environment=SLSKD_DOWNLOADS_PATH=<path-to-slskd-downloads>' /etc/systemd/system/droppedneedle.service
       fi
       sed -i 's|^ExecStart=.*|ExecStart=/opt/droppedneedle/venv/bin/python -m maintenance.automatic_upgrade --start-target|' /etc/systemd/system/droppedneedle.service
+      if grep -q '^Environment=COMMIT_TAG=' /etc/systemd/system/droppedneedle.service; then
+        sed -i "s|^Environment=COMMIT_TAG=.*|Environment=COMMIT_TAG=v$(<~/.droppedneedle)|" /etc/systemd/system/droppedneedle.service
+      else
+        sed -i "\|=8688$|a Environment=COMMIT_TAG=v$(<~/.droppedneedle)" /etc/systemd/system/droppedneedle.service
+      fi
     fi
 
     systemctl daemon-reload

install/droppedneedle-install.sh

@@ -44,6 +44,7 @@ User=root
 WorkingDirectory=/opt/droppedneedle/backend
 Environment=ROOT_APP_DIR=/opt/droppedneedle/backend
 Environment=PORT=8688
+Environment=COMMIT_TAG=v$(<~/.droppedneedle)
 # Environment=SLSKD_DOWNLOADS_PATH=<path-to-slskd-downloads>
 ExecStart=/opt/droppedneedle/venv/bin/python -m maintenance.automatic_upgrade --start-target
 Restart=on-failure