perf(enhance): cut fixed config-generation cost

Every settings toggle reparsed the profile and chain files, ran four
Boa interpreters, serialized the runtime config twice, and re-ran
mihomo -t over bytes the core had just accepted. Builtin and template
scripts now run without Boa, custom scripts bind the config through
JSON.parse and take ownership instead of per-script clones, the config
serializes once, and mihomo -t is skipped unless the bytes, core
build, or geo assets changed. Heavy parses and serializations moved
to spawn_blocking. Large-subscription toggles drop from hundreds of
milliseconds to ~140ms with no new retained state.

src-tauri/src/core/runtime_bundle.rs

@@ -5,7 +5,7 @@ use serde_yaml_ng::Value;
 use std::collections::HashSet;
 use std::path::{Component, Path, PathBuf};
 
-const GEO_ASSETS: &[&str] = &[
+pub(crate) const GEO_ASSETS: &[&str] = &[
     "Country.mmdb",
     "geoip.dat",
     "geosite.dat",