fix(docs): correct embeddings provider count and guard the table against drift

The refreshed provider table said 12 embedders; EmbedderFactory registers 11.
The other three rows were right, so the table drifted silently again inside the
commit that was fixing it drifting.

Add tests/test_agents_md_provider_counts.py, which parses the AGENTS.md provider
table and asserts each documented count equals len(<Factory>.provider_to_class).
Verified it fails on the 12 and passes on 11.

AGENTS.md

@@ -342,7 +342,7 @@ The SDK uses a consistent plugin architecture across 4 categories. Each category
 |----------|-------|---------|
 | **LLMs** | 18 | OpenAI, Anthropic, AWS Bedrock, Azure OpenAI, Gemini, Groq, Ollama, Together, DeepSeek, vLLM, LiteLLM, LM Studio, xAI |
 | **Vector Stores** | 25 | Qdrant, Pinecone, Chroma, Weaviate, Milvus, MongoDB, Redis, Elasticsearch, pgvector, Supabase, Faiss, S3 Vectors |
-| **Embeddings** | 12 | OpenAI, Azure OpenAI, Gemini, HuggingFace, FastEmbed, Together, AWS Bedrock, Ollama, Vertex AI |
+| **Embeddings** | 11 | OpenAI, Azure OpenAI, Gemini, HuggingFace, FastEmbed, Together, AWS Bedrock, Ollama, Vertex AI |
 | **Rerankers** | 5 | Cohere, HuggingFace, LLM-based, Sentence Transformer, Zero Entropy |
 
 ### Two Usage Modes

tests/test_agents_md_provider_counts.py

@@ -0,0 +1,37 @@
+"""Drift test: the provider counts in AGENTS.md must match the factory registries."""
+
+import re
+from pathlib import Path
+
+import pytest
+
+from mem0.utils.factory import (
+    EmbedderFactory,
+    LlmFactory,
+    RerankerFactory,
+    VectorStoreFactory,
+)
+
+AGENTS_MD = Path(__file__).resolve().parents[1] / "AGENTS.md"
+
+ROW_TO_FACTORY = {
+    "LLMs": LlmFactory,
+    "Vector Stores": VectorStoreFactory,
+    "Embeddings": EmbedderFactory,
+    "Rerankers": RerankerFactory,
+}
+
+
+def _documented_counts() -> dict[str, int]:
+    rows = re.findall(r"^\|\s*\*\*(.+?)\*\*\s*\|\s*(\d+)\s*\|", AGENTS_MD.read_text(), re.M)
+    return {name: int(count) for name, count in rows}
+
+
+@pytest.mark.parametrize("row_name,factory", ROW_TO_FACTORY.items())
+def test_documented_count_matches_registry(row_name, factory):
+    documented = _documented_counts()
+    assert row_name in documented, f"AGENTS.md provider table has no {row_name!r} row"
+    assert documented[row_name] == len(factory.provider_to_class), (
+        f"AGENTS.md says {documented[row_name]} {row_name} but "
+        f"{factory.__name__}.provider_to_class has {len(factory.provider_to_class)}"
+    )