builder+vm: unify method calls via emit_unified_call; add RouterPolicy trace; finalize LocalSSA/BlockSchedule guards; docs + selfhost quickstart

- Unify standard method calls to emit_unified_call; route via RouterPolicy and apply rewrite::{special,known} at a single entry.\n- Stabilize emit-time invariants: LocalSSA finalize + BlockSchedule PHI→Copy→Call ordering; metadata propagation on copies.\n- Known rewrite default ON (userbox only, strict guards) with opt-out flag NYASH_REWRITE_KNOWN_DEFAULT=0.\n- Expand TypeAnnotation whitelist (is_digit_char/is_hex_digit_char/is_alpha_char/Map.has).\n- Docs: unified-method-resolution design note; Quick Reference normalization note; selfhosting/quickstart.\n- Tools: add tools/selfhost_smoke.sh (dev-only).\n- Keep behavior unchanged for Unknown/core/user-instance via BoxCall fallback; all tests green (quick/integration).

docs/reference/language/quick-reference.md

@@ -11,8 +11,11 @@ Keywords (reserved)
 
 Expressions and Calls
 - Function call: `f(a, b)`
-- Method call: `obj.m(a, b)` — internally rewritten to function form: `Class.m(me: obj, a, b)`
-  - Rewrite is default‑ON; backends (VM/LLVM/Ny) receive the unified call shape.
+- Method call: `obj.m(a, b)` — internally normalized to function form: `Class.m(me: obj, a, b)`
+  - Default‑ON（P4）: Known 受信者かつ関数が一意に存在する場合に正規化（userbox 限定）。
+  - それ以外（Unknown/core/user‑instance）は安全に BoxCall へフォールバック（挙動不変）。
+  - 環境で無効化: `NYASH_REWRITE_KNOWN_DEFAULT=0`（開発時の切替用）。
+  - バックエンド（VM/LLVM/Ny）は統一形状の呼び出しを受け取る。
 - Member: `obj.field` or `obj.m`
 
 Display & Conversion