add experimental thermal camera streaming support (#12)

## What does this PR do?

<!-- Brief description of the change -->

## Why?

<!-- What problem does this solve? Link to issue if applicable. -->

Closes #

## Checklist

- [ ] Tests pass (`pytest`)
- [ ] Linting passes (`ruff check .`)
- [ ] New code has type hints
- [ ] Updated CHANGELOG.md (if user-facing change)
- [ ] Tested on target hardware (if applicable)

Author: mwschulte23

.gitignore

@@ -52,3 +52,9 @@ htmlcov/
 # Local config
 .env
 .env.local
+
+# macOS
+.DS_Store
+
+# Logs
+*.log

examples/thermal_camera.py

@@ -0,0 +1,88 @@
+"""
+Thermal camera streaming to Plexus.
+
+Reads from any supported thermal camera and sends frames to Plexus using
+the SDK's send_thermal_frame() method. The gateway relays colorized JPEG
+frames to the app, along with temperature range and (for small sensors)
+per-pixel temperature data.
+
+Supported hardware (--camera argument):
+    sim         Simulated camera — no hardware needed (default)
+    mlx90640    MLX90640 32×24 I2C sensor (pip install adafruit-circuitpython-mlx90640)
+    mlx90641    MLX90641 16×12 I2C sensor (pip install adafruit-circuitpython-mlx90641)
+    usb         USB thermal camera in Y16 format (InfiRay, Topdon, Seek, etc.)
+
+Run:
+    export PLEXUS_API_KEY=plx_xxx
+    python thermal_camera.py
+    python thermal_camera.py --camera mlx90640
+    python thermal_camera.py --camera usb --device 2
+"""
+
+import argparse
+import sys
+import time
+
+from plexus import Plexus
+from plexus.cameras.thermal import NoCameraFound, ThermalSource
+
+CAMERA_ID = "thermal"
+FPS = 5
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Stream thermal camera to Plexus.")
+    parser.add_argument(
+        "--camera",
+        choices=["sim", "mlx90640", "mlx90641", "usb"],
+        default=None,
+        help="Camera driver (default: auto-detect)",
+    )
+    parser.add_argument(
+        "--device",
+        type=int,
+        default=0,
+        help="USB video device index (default: 0)",
+    )
+    args = parser.parse_args()
+
+    hint = args.device if args.camera == "usb" else args.camera
+    try:
+        cam = ThermalSource.open(hint)
+    except NoCameraFound as e:
+        print(f"Error: {e}", file=sys.stderr)
+        sys.exit(1)
+
+    px = Plexus(transport="ws")
+    px.wait_connected()
+
+    interval = 1.0 / FPS
+    frame_count = 0
+    print(f"Streaming {cam.width}×{cam.height} thermal at {FPS} fps — Ctrl-C to stop")
+
+    try:
+        while True:
+            t0 = time.time()
+
+            temps = cam.read_frame()
+            px.send_thermal_frame(temps, camera_id=CAMERA_ID)
+
+            frame_count += 1
+            if frame_count % 50 == 0:
+                print(f"  {frame_count} frames sent")
+
+            elapsed = time.time() - t0
+            wait = interval - elapsed
+            if wait > 0:
+                time.sleep(wait)
+
+    except KeyboardInterrupt:
+        pass
+    finally:
+        cam.close()
+        px.stop()
+        print(f"Done. {frame_count} frames sent.")
+
+
+if __name__ == "__main__":
+    main()

plexus/cameras/__init__.py

@@ -0,0 +1,25 @@
+from plexus.cameras.thermal import (
+    NoCameraFound,
+    MLX90640Camera,
+    MLX90641Camera,
+    SimulatedThermalCamera,
+    ThermalCamera,
+    ThermalFrame,
+    ThermalSource,
+    USBThermalCamera,
+    build_thermal_frame,
+    encode_frame,
+)
+
+__all__ = [
+    "NoCameraFound",
+    "MLX90640Camera",
+    "MLX90641Camera",
+    "SimulatedThermalCamera",
+    "ThermalCamera",
+    "ThermalFrame",
+    "ThermalSource",
+    "USBThermalCamera",
+    "build_thermal_frame",
+    "encode_frame",
+]