refactor!: rename slhx to hemx

Rename the tracked product identity, crate/package names, Rust paths/macros, generated artifacts, runtime files, public attributes, examples, docs, requirements, and tests from slhx to hemx without compatibility shims.

Verified with cargo run -p hemx-xtask -- test, cargo test -p hemx-derive --test compile_fail, cargo test -p hemx-js, cargo test -p hemx-axum, cargo test -p hemx-v0-examples, cargo check --workspace, redgate list, redgate refs, redgate health --strict, git diff --check, and git grep/ls-files legacy-name audits.

req: misc/001

req: codegen/001

req: component/004

req: runtime/001

hemx-derive/tests/surface.rs

@@ -0,0 +1,21 @@
+use hemx_derive::{component, surface};
+
+#[component]
+mod local_component {
+    pub const EXISTING: u8 = 1;
+}
+
+#[surface]
+mod ui {
+    pub const EXISTING: u8 = 1;
+}
+
+#[test]
+fn surface_macro_preserves_inline_module_with_generated_file() {
+    assert_eq!(ui::EXISTING, 1);
+}
+
+#[test]
+fn component_macro_preserves_inline_module_without_generated_symbols() {
+    assert_eq!(local_component::EXISTING, 1);
+}