Initial checkpoint: Crazyflie mission client (DearPyGui)

Two-step ARM -> LAUNCH -> LAND flight flow for a Crazyflie + Flow v2 deck:

- controller.py: cflib link + flight logic on one worker thread with a
  command queue. Supervisor arming, Kalman estimator reset/convergence
  wait, high-level-commander takeoff/land, configurable hover height
  (0.2-2.0 m), emergency stop, graceful land-on-shutdown, thread-safe
  snapshot()/scan(). States: DISCONNECTED/CONNECTING/READY/ARMING/ARMED/
  FLYING/LANDING/EMERGENCY/ERROR.
- mission_client.py: DearPyGui front-end, manual render loop polling
  snapshot() each frame. Context button ARM(green)->LAUNCH(blue)->LAND
  (yellow), secondary Disarm, hover-height slider, console log, and an
  Estimator state panel (x/y/z, yaw, flow counts) for drift inspection.
- uv-managed (pyproject.toml + uv.lock); run `uv run mission_client.py`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,17 @@
+[project]
+name = "crazyflie-mission-client"
+version = "0.1.0"
+description = "Tkinter mission client that flies a Crazyflie + Flow v2 deck to a 1 m hover"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = [
+    # Crazyflie radio link, logging, commander, supervisor arming API.
+    # 0.1.25 is the first release with cf.supervisor.send_arming_request().
+    "cflib>=0.1.25",
+    # Immediate-mode GUI (same binding as the test-stand app).
+    "dearpygui>=2.0",
+]
+
+[tool.uv]
+# Flat-module application, not an installable package — don't try to build it.
+package = false