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.

lib/Fs.bux

@@ -1,19 +1,19 @@
 module Std::Fs {
 
-extern func bux_dir_exists(path: String) -> int;
-extern func bux_mkdir_if_needed(path: String) -> int;
-extern func bux_list_dir(dir: String, ext: String, out_count: *int) -> *String;
+    extern func bux_dir_exists(path: String) -> int;
+    extern func bux_mkdir_if_needed(path: String) -> int;
+    extern func bux_list_dir(dir: String, ext: String, out_count: *int) -> *String;
 
-func DirExists(path: String) -> bool {
-    return bux_dir_exists(path) != 0;
-}
+    func DirExists(path: String) -> bool {
+        return bux_dir_exists(path) != 0;
+    }
 
-func Mkdir(path: String) -> bool {
-    return bux_mkdir_if_needed(path) != 0;
-}
+    func Mkdir(path: String) -> bool {
+        return bux_mkdir_if_needed(path) != 0;
+    }
 
-func ListDir(dir: String, ext: String, count: *int) -> *String {
-    return bux_list_dir(dir, ext, count);
-}
+    func ListDir(dir: String, ext: String, count: *int) -> *String {
+        return bux_list_dir(dir, ext, count);
+    }
 
 }