docs: Field Notes draft, DEPLOY guide + social post; bundle warmup asset

- FIELD_NOTES.md: blog draft (Field Notes badge) telling the story + decisions
- DEPLOY.md: exact HF Space/ZeroGPU deploy steps + social post draft
- assets/warmup.jpg + app.py warmup path made self-contained (Space-safe)

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

app.py

@@ -162,7 +162,7 @@ if __name__ == "__main__":
     if os.environ.get("IRIS_WARMUP") == "1":
         print("Warmup...", flush=True)
         try:
-            vlm.describe(str(HERE.parent / "viability" / "samples" / "indoor.jpg"), "test")
+            vlm.describe(str(HERE / "assets" / "warmup.jpg"), "test")
             stt.transcribe(tts.synthesize("test"))
             print("Warmup OK", flush=True)
         except Exception as e: