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/function_emission.rs

@@ -0,0 +1,57 @@
+//! FunctionEmissionBox — MirFunction 直編集時の発行ヘルパ（仕様不変・dev補助）
+//!
+//! MirBuilder 経由ではなく MirFunction/BasicBlock を直接編集する箇所（dev 補助）向けに、
+//! よく使う Const/Return/Jump の発行を薄い関数で提供する。
+
+use crate::mir::{BasicBlockId, ConstValue, MirFunction, MirInstruction, ValueId};
+
+#[inline]
+pub fn emit_const_integer(f: &mut MirFunction, bb: BasicBlockId, val: i64) -> ValueId {
+    let dst = f.next_value_id();
+    if let Some(block) = f.get_block_mut(bb) {
+        block.add_instruction(MirInstruction::Const { dst, value: ConstValue::Integer(val) });
+    }
+    dst
+}
+
+#[inline]
+pub fn emit_const_bool(f: &mut MirFunction, bb: BasicBlockId, val: bool) -> ValueId {
+    let dst = f.next_value_id();
+    if let Some(block) = f.get_block_mut(bb) {
+        block.add_instruction(MirInstruction::Const { dst, value: ConstValue::Bool(val) });
+    }
+    dst
+}
+
+#[inline]
+pub fn emit_const_string<S: Into<String>>(f: &mut MirFunction, bb: BasicBlockId, s: S) -> ValueId {
+    let dst = f.next_value_id();
+    if let Some(block) = f.get_block_mut(bb) {
+        block.add_instruction(MirInstruction::Const { dst, value: ConstValue::String(s.into()) });
+    }
+    dst
+}
+
+#[inline]
+pub fn emit_const_void(f: &mut MirFunction, bb: BasicBlockId) -> ValueId {
+    let dst = f.next_value_id();
+    if let Some(block) = f.get_block_mut(bb) {
+        block.add_instruction(MirInstruction::Const { dst, value: ConstValue::Void });
+    }
+    dst
+}
+
+#[inline]
+pub fn emit_return_value(f: &mut MirFunction, bb: BasicBlockId, value: ValueId) {
+    if let Some(block) = f.get_block_mut(bb) {
+        block.add_instruction(MirInstruction::Return { value: Some(value) });
+    }
+}
+
+#[inline]
+pub fn emit_jump(f: &mut MirFunction, bb: BasicBlockId, target: BasicBlockId) {
+    if let Some(block) = f.get_block_mut(bb) {
+        block.add_instruction(MirInstruction::Jump { target });
+    }
+}
+