feat: lifetime elision, tooling CI, registry, and LSP locals

Ship the QUALITY_PLAN stretch from ownership through ecosystem: C.1
lifetime elision (bootstrap + selfhost), bux fmt/test/doc CI hooks,
stdlib goldens, package registry (bux search/add), and LSP 0.4
position-sensitive locals with inferred let types. Full-tree format
pass plus Map/Set remove double-free fix.

registry/packages/greet/src/Greet.bux

@@ -0,0 +1,14 @@
+// greet — demo registry package (E.1)
+module Greet {
+
+    /// Return a greeting for `name`.
+    func Greet_Hello(name: String) -> String {
+        return String_Concat("Hello, ", String_Concat(name, "!"));
+    }
+
+    /// Return the package version string.
+    func Greet_Version() -> String {
+        return "0.1.1";
+    }
+
+}