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/build.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+# Build the el WASM package.
+#
+# Requires wasm-pack:
+#   cargo install wasm-pack
+#
+# Output: crates/el-wasm/pkg/
+#   el_wasm_bg.wasm   — the compiled WebAssembly module
+#   el_wasm.js        — ES module JS bindings generated by wasm-bindgen
+#   el_wasm.d.ts      — TypeScript type definitions
+#   package.json      — npm package metadata
+
+set -euo pipefail
+cd "$(dirname "$0")"
+
+echo "Building el WASM runtime..."
+wasm-pack build --target web --out-dir pkg -- --features wasm
+
+echo ""
+echo "Done. Output in crates/el-wasm/pkg/"
+echo ""
+ls -lh pkg/*.wasm pkg/*.js 2>/dev/null || ls pkg/