Suya OCR API — vLLM-backed, OpenAI-compatible OCR service

FastAPI service wrapping the Surya-OCR-2 model (datalab-to) served through vLLM:
legacy /v1/api/ai/* endpoints, an OpenAI-compatible /v1/chat/completions endpoint,
a coalescing request batcher, a local OCR CLI, Docker packaging, multilingual
example outputs, and quantization/concurrency benchmarks.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_cer_divergence.py

@@ -0,0 +1,18 @@
+from scripts.cer_divergence import cer
+
+
+def test_identical_text_is_zero():
+    assert cer("hello world", "hello world") == 0.0
+
+
+def test_single_substitution():
+    # 1 edit over 5 reference chars
+    assert cer("hello", "hallo") == 0.2
+
+
+def test_empty_reference_with_output_is_one():
+    assert cer("", "abc") == 1.0
+
+
+def test_empty_both_is_zero():
+    assert cer("", "") == 0.0