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-wasm/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "el-wasm"
+description = "Engram language WebAssembly runtime — runs .el programs natively in browsers"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+el-compiler = { workspace = true }
+wasm-bindgen = { workspace = true, optional = true }
+serde     = { workspace = true }
+serde_json = { workspace = true }
+getrandom = { workspace = true, optional = true }
+
+[features]
+# Enable the wasm-bindgen JS API. Pass `--features wasm` to wasm-pack.
+wasm = ["dep:wasm-bindgen", "dep:getrandom"]
+
+[dev-dependencies]
+wasm-bindgen-test = "0.3"