feat(lsp): method call hierarchy for extend Type / .Method (0.9)

Index methods inside extend/impl blocks and include .Method( call sites
in the call graph so IDEs can navigate receiver methods.

- analyzeFile: track extend/impl brace scope; kind=method + container
- Call hierarchy treats methods as callables; display Type.Method
- smoke_lsp_method_hierarchy (Scale→Len, Main→Scale)

docs/QUALITY_PLAN.md

@@ -1,7 +1,7 @@
 # Bux — План към „добър“ език (v0.5 → v1.0)
 
 > **Дата:** 2026-07-19  
-> **Текущо:** v0.5.x — multi-file #line, **selfhost CI smoke**, LSP 0.8, Nexus KA  
+> **Текущо:** v0.5.x — multi-file #line, selfhost CI, **LSP 0.9 method hierarchy**, Nexus KA  
 > **Цел:** Език, с който се пишат реални проекти комфортно, безопасно (по избор) и с надежден toolchain.
 
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