Add scaffolding for query-ops crate

Cargo.lock

@@ -282,6 +282,10 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "query-ops"
+version = "0.1.0"
+
 [[package]]
 name = "quote"
 version = "1.0.45"

crates/geomerge-demo/README.md

@@ -4,7 +4,7 @@ This demo shows how to store and read data from Geomerge.
 
 The demo:
 
-1. loads the compiled [`paths.json`](../../external/geomerge/crates/geomerge/tests/data/paths.json) schema,
+1. loads the compiled [`paths.json`](https://git.sgai.uk/vincent_liu/geomerge/-/raw/main/crates/geomerge/tests/data/paths.json) schema,
 2. creates a Geomerge store,
 3. inserts a small graph dataset in one transaction,
 4. reads the inserted edge back,

crates/query-ops/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "query-ops"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]

crates/query-ops/src/lib.rs

@@ -0,0 +1,10 @@
+//! Physical operators for a small query-plan executor.
+//!
+//! Targeted scope:
+//! - atom scans with repeated-variable filtering and variable-binding output
+//! - semijoins
+//! - natural joins
+//!
+//! The operators are intended to be composed by hand into a small plan and
+//! evaluated against in-memory relations. Integration with an external query
+//! plan IR is out of scope for this crate.