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).

src/mir/builder/lifecycle.rs

@@ -279,12 +279,9 @@ impl super::MirBuilder {
             // parameter slot (unused in body)
             let _param = f.next_value_id();
             f.params.push(_param);
-            // body: const 1; return it
-            let one = f.next_value_id();
-            if let Some(bb) = f.get_block_mut(entry) {
-                bb.add_instruction(MirInstruction::Const { dst: one, value: ConstValue::Integer(1) });
-                bb.add_instruction(MirInstruction::Return { value: Some(one) });
-            }
+            // body: const 1; return it（FunctionEmissionBox を使用）
+            let one = crate::mir::function_emission::emit_const_integer(&mut f, entry, 1);
+            crate::mir::function_emission::emit_return_value(&mut f, entry, one);
             module.add_function(f);
         }