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-migrate/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "engram-migrate"
+version = "0.1.0"
+edition = "2021"
+description = "CLI tool: migrate a Neuron SQLite database into an Engram sled store"
+license = "MIT"
+
+[[bin]]
+name = "engram-migrate"
+path = "src/main.rs"
+
+[dependencies]
+engram-core = { path = "../engram-core", features = ["sled-backend", "migration"] }