feat(svrnty-vision): Phase 4b complete — full impl + e2e test suite

- palette.py + rembg.py: implement from stubs (Pillow median-cut + rembg u2net)
- vlm.py: rename Spark2→steev (Strix Halo / Ollama); bump max_tokens 1024→4096
  (qwen3-vl:32b thinking mode consumes budget tokens — 4096 min for valid output)
- settings.py: rename spark2_vlm_*/spark1_flux_* → vlm_*/flux_*; real defaults
  (steev 100.88.167.87:11434 Ollama, gx10 100.90.100.10:8188 ComfyUI)
- tests/: conftest.py + test_palette.py + test_rembg.py + test_integration_e2e.py
  (28 unit + 10 integration; 38/38 passing — VLM raw/polished/ugc + FLUX render)
- CLAUDE.md: rewrite to accurate phase status + infra + layout
- requirements.txt + pyproject.toml: add Pillow, rembg, pytest-asyncio deps

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/conftest.py

@@ -0,0 +1,46 @@
+"""Shared fixtures for svrnty-vision test suite."""
+
+from __future__ import annotations
+
+import base64
+import io
+
+import pytest
+from fastapi.testclient import TestClient
+from PIL import Image
+
+from svrnty_vision.server import app
+
+
+@pytest.fixture(scope="session")
+def client() -> TestClient:
+    return TestClient(app)
+
+
+@pytest.fixture(scope="session")
+def red_png_b64() -> str:
+    """100×100 solid-red PNG encoded as base64 — minimal valid image for all endpoints."""
+    img = Image.new("RGB", (100, 100), color=(220, 50, 50))
+    buf = io.BytesIO()
+    img.save(buf, format="PNG")
+    return base64.b64encode(buf.getvalue()).decode("ascii")
+
+
+@pytest.fixture(scope="session")
+def gradient_png_b64() -> str:
+    """200×200 RGB gradient — more realistic for VLM + palette tests."""
+    img = Image.new("RGB", (200, 200))
+    for x in range(200):
+        for y in range(200):
+            img.putpixel((x, y), (x, y, 128))
+    buf = io.BytesIO()
+    img.save(buf, format="PNG")
+    return base64.b64encode(buf.getvalue()).decode("ascii")
+
+
+def pytest_configure(config: pytest.Config) -> None:
+    config.addinivalue_line(
+        "markers",
+        "integration: live service tests — require Tailscale + running Spark hosts. "
+        "Run with: pytest -m integration",
+    )