feat(edgecfg): Phase 268-270 savepoint (if_form adoption + Pattern9 minimal loop SSOT)

src/mir/builder/control_flow/joinir/patterns/mod.rs

@@ -82,6 +82,7 @@ pub(in crate::mir::builder) mod pattern5_infinite_early_exit; // Phase 131-11
 pub(in crate::mir::builder) mod pattern6_scan_with_init; // Phase 254 P0: index_of/find/contains pattern
 pub(in crate::mir::builder) mod pattern7_split_scan; // Phase 256 P0: split/tokenization with variable step
 pub(in crate::mir::builder) mod pattern8_scan_bool_predicate; // Phase 259 P0: boolean predicate scan (is_integer/is_valid)
+pub(in crate::mir::builder) mod pattern9_accum_const_loop; // Phase 270 P1: accumulator const loop (橋渡しパターン)
 pub(in crate::mir::builder) mod pattern_pipeline;
 pub(in crate::mir::builder) mod router;
 pub(in crate::mir::builder) mod trim_loop_lowering; // Phase 180: Dedicated Trim/P5 lowering module