chore: Remove unused imports in normalized_shadow modules

Cleaned up unused imports after Phase 143 execution fix (5e662eaaf).

**Priority files (Phase 143)**:
- if_as_last_join_k.rs: removed ValueId, BTreeMap
- loop_true_break_once.rs: added #[cfg(test)] for test-only imports
- post_if_post_k.rs: removed ValueId, BTreeMap
- normalized_helpers.rs: added #[cfg(test)] for Span

**Additional cleanup**:
- contract_checks.rs: removed BasicBlockId
- joinir/mod.rs: removed Info struct re-exports (functions kept)
- patterns/mod.rs: removed Info struct re-exports (functions kept)
- ast_feature_extractor.rs: removed EscapeSkipPatternInfo
- plan_box.rs: added #[cfg(test)] for PlanKind

**Verification**:
- 0 unused import warnings (was 20+)
- All 69 normalized_shadow tests pass
- Clean build with --release

Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs/development/current/main/phases/phase-143-loopvocab/README.md

@@ -103,7 +103,7 @@ k_else(unused in P0)
 - `tools/smokes/v2/profiles/integration/apps/phase143_loop_true_if_break_vm.sh`
 - `tools/smokes/v2/profiles/integration/apps/phase143_loop_true_if_break_llvm_exe.sh`
 
-Expected exit code: 1
+Expected exit code: 7
 
 #### Step 9: Documentation (THIS FILE)
 
@@ -134,6 +134,32 @@ Expected exit code: 1
 
 ---
 
+## P1: Continue Vocabulary (COMPLETE ✅)
+
+### Summary
+
+`loop(true) { if(cond_pure) continue }` を語彙として受理し、Normalized shadow 経路で「コンパイル/実行が落ちない」ことを固定する。
+
+### Important note (P1 scope)
+
+P1 の fixture は **意図的に non-terminating**（break/else/state update を含まない）である。
+
+- 条件式は `ExprLoweringScope::PureOnly` で lowering できることを検証する（スコープ境界の固定）。
+- ただし P1 では continue を「条件分岐で skip する」語彙までに留め、bridge 側の Jump(early-return) と混線させないため、
+  実際の JoinIR emission は `loop_step` への tail call を基本にする。
+
+### Fixture / smokes
+
+- Fixture: `apps/tests/phase143_loop_true_if_continue_min.hako`
+- VM smoke (timeout contract):
+  - `tools/smokes/v2/profiles/integration/apps/phase143_loop_true_if_continue_vm.sh`
+  - Contract: `HAKO_VM_MAX_STEPS=0` + `timeout ${SMOKES_P143_CONTINUE_TIMEOUT_SECS:-1}` → exit code `124`
+- LLVM EXE smoke (timeout contract):
+  - `tools/smokes/v2/profiles/integration/apps/phase143_loop_true_if_continue_llvm_exe.sh`
+  - Contract: `RUN_TIMEOUT_SECS=${SMOKES_P143_CONTINUE_TIMEOUT_SECS:-1}` → exit code `124`
+
+---
+
 ## Design Principles
 
 ### Out-of-Scope Handling