rename crates/ to engrams/, bindings/ to receptors/

- crates/ → engrams/ (Rust engrams live here)
- bindings/ → receptors/ (cross-language access points into the graph)
- Cargo.toml workspace paths updated

engram/engrams/engram-core/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "engram-core"
+version = "0.1.1"
+edition = "2021"
+description = "Engram — native memory substrate for accumulating intelligence"
+license = "MIT"
+
+[features]
+default = ["sled-backend"]
+sled-backend = ["dep:sled"]
+wasm = []
+migration = ["dep:rusqlite"]
+
+[dependencies]
+sled = { version = "0.34", optional = true }
+uuid = { version = "1", features = ["v4", "serde"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+bincode = "1"
+anyhow = "1"
+thiserror = "1"
+instant-distance = { version = "0.6", features = ["with-serde"] }
+rusqlite = { version = "0.31", optional = true }
+
+[dev-dependencies]
+tempfile = "3"