Add Blender plugin (#134)

* Unbind hostname to allow localhost submissions

* Fix issue where multiple cameras were outputting to the same directory

* Add Blender plugin

addons/blender/zordon_blender/README.md

@@ -0,0 +1,153 @@
+# Zordon Blender Add-on
+
+Submit the current Blender file to a Zordon render server from Blender's Render
+properties panel.
+
+## Features
+
+- Submit the current `.blend` file directly to `POST /api/jobs`.
+- Choose a configured Zordon server from Blender.
+- Test the server connection before submitting.
+- Save the current file before upload.
+- Default job and output names to the `.blend` filename.
+- Use the current scene frame range, render resolution, FPS, and image format.
+- Select one or more cameras for submission.
+- Submit multiple selected cameras as camera-specific child jobs.
+
+## Install
+
+1. In Blender, open `Edit > Preferences > Add-ons`.
+2. Click `Install...`.
+3. Select `addons/blender/zordon_blender.zip`.
+4. Enable `Zordon Render Submitter`.
+
+## Configure Servers
+
+Use `Discover Servers` to find Zordon servers advertised with Zeroconf.
+Discovered servers are merged into the configured server list.
+
+You can also open the add-on preferences and edit `Servers` manually.
+
+Use a comma-separated list:
+
+```text
+localhost:8080, render-node.local:8080
+```
+
+The selected server appears in `Properties > Render > Zordon`.
+
+If Blender is running on the same machine as Zordon, `localhost:8080` should
+work. If Zordon is running on another machine, use that machine's hostname or IP
+address.
+
+Start the Zordon server before testing the connection:
+
+```bash
+python server.py
+```
+
+Discovery first tries Python's `zeroconf` package if it is available inside
+Blender. If it is not available, the add-on falls back to the macOS `dns-sd`
+command when present.
+
+## Submit A Job
+
+1. Open or save a `.blend` file.
+2. Choose a Zordon server in `Properties > Render > Zordon`.
+3. Click `Test Connection`.
+4. Set the job name, output name, and notes if needed.
+5. Choose one or more cameras. At least one camera is always required.
+6. Click `Submit Current File`.
+
+The addon uploads the current `.blend` to `POST /api/jobs` as multipart form
+data. It uses the current scene frame range, render resolution, FPS, and image
+format.
+
+Job name and output name default to the current `.blend` filename.
+
+If one camera is selected, the job renders that camera. If multiple cameras are
+selected, the addon submits camera-specific child jobs so each camera renders as
+its own Zordon job.
+
+Use `All` to select every camera or `Active Only` to render just the active
+scene camera.
+
+## Camera Behavior
+
+At least one camera must be selected. The add-on prevents unchecking the final
+selected camera.
+
+When one camera is selected, the add-on sends a single job with:
+
+```json
+{
+  "args": {
+    "camera": "Camera"
+  }
+}
+```
+
+When multiple cameras are selected, the add-on sends `child_jobs`. Each child job
+gets its own camera argument and output name suffix, such as:
+
+```json
+{
+  "name": "scene_Camera-001",
+  "output_path": "scene_Camera-001",
+  "args": {
+    "camera": "Camera.001"
+  }
+}
+```
+
+## Troubleshooting
+
+### Could Not Reach Zordon
+
+Make sure the Zordon server is running and reachable from Blender.
+
+Check from a terminal:
+
+```bash
+curl http://localhost:8080/api/heartbeat
+```
+
+If the server is remote, replace `localhost` with the server hostname or IP.
+
+### No Cameras Found
+
+Add at least one Blender camera to the scene before submitting.
+
+### Output Files Already Exist
+
+Multiple camera jobs should use camera-specific output names. If they collide,
+make sure the Zordon server includes the output-path fix that preserves child
+job `output_path` values.
+
+## Packaging
+
+The add-on source lives at:
+
+```text
+addons/blender/zordon_blender/
+```
+
+The installable archive is:
+
+```text
+addons/blender/zordon_blender.zip
+```
+
+Rebuild the archive from `addons/blender`:
+
+```bash
+python3 -m zipfile -c zordon_blender.zip zordon_blender
+```
+
+## Notes
+
+- The add-on is dependency-free and uses Blender's bundled Python standard
+  library.
+- Only `http://` Zordon servers are currently supported.
+- `Save Before Submit` is enabled by default so the uploaded file matches the
+  current Blender state.