feat: portable cross-runtime code-simplification skill

ast-grep-driven detection + ranking into a JSON ledger, two-track apply
(deterministic autofix + model span-edits), configurable report/apply modes.
Rule packs for JS/TS, Python, Go, Rust, Java; Svelte/SvelteKit support via
project tooling + opt-in grammar. Runtime-neutral SKILL.md (Agent Skills spec).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

fixtures/rust/messy.rs

@@ -0,0 +1,21 @@
+pub fn decide(ready: bool, blocked: bool) -> bool {
+    if ready == true {
+        return false;
+    }
+    if blocked == false {
+        return true;
+    }
+    false
+}
+
+pub fn price(base: i64, qty: i64, tax_rate: i64, discount: i64, shipping: i64) -> i64 {
+    let mut total = base * qty;
+    if qty > 0 {
+        if tax_rate > 0 {
+            if total > 5000 {
+                total = total - discount;
+            }
+        }
+    }
+    total + shipping
+}