rename crates/ to engrams/; add el-compiler el package with bootstrap artifact

- crates/ → engrams/ (Rust engrams live here)
- el-compiler/ added: el self-hosting compiler as an el package
  - src/{compiler,lexer,parser,codegen}.el
  - bootstrap/el-compiler.elc (114KB, Rust-compiled seed)
- el.toml Cargo.toml workspace paths updated
- neuron-rs cross-repo path deps fixed (were pointing to products/ instead of foundation/)

engrams/el-lint/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "el-lint"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+el-lexer = { path = "../el-lexer" }
+el-parser = { path = "../el-parser" }
+el-types = { path = "../el-types" }
+el-arch = { path = "../el-arch" }
+el-fmt = { path = "../el-fmt" }
+thiserror = "2"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+
+[dev-dependencies]
+el-lexer = { path = "../el-lexer" }
+el-parser = { path = "../el-parser" }