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.

tests/stdlib_golden/collections/bux.toml

@@ -0,0 +1,7 @@
+[Package]
+Name    = "stdlib_collections"
+Version = "0.1.0"
+Type    = "bin"
+
+[Build]
+Output = "Bin"