docs: add CLAUDE.md with pre-push checklist

Author: anoop-narang

CLAUDE.md

@@ -0,0 +1,17 @@
+# CLAUDE.md
+
+## Project Overview
+
+A DataFusion extension crate for vector similarity search (ANN) using USearch HNSW indices. Provides optimizer rules, UDFs (l2_distance, cosine_distance, negative_dot), and pluggable lookup providers (Parquet, SQLite) for retrieving non-embedding columns by key.
+
+## Git Commits
+
+Use conventional format: `<type>(<scope>): <subject>` where type = feat|fix|docs|style|refactor|test|chore|perf. Subject: 50 chars max, imperative mood ("add" not "added"), no period.
+
+## Pre-Push Checklist
+
+Always run these before pushing:
+
+1. `cargo fmt --check` — fix any formatting issues
+2. `cargo clippy -- -D warnings` — no warnings allowed
+3. `cargo test --features sqlite-provider` — all tests must pass (sqlite-provider feature needed for SQLite provider tests)