docs(phase-91): Update Phase 91 README with Step 2 completion status

### Updates

#### 1. Status Section
- Updated Status to reflect all completed steps (1, 2-A/B/D, 2-E)
- Documented parity verification success

#### 2. Completion Status Section (NEW)
- Added dedicated section for Phase 91 Step 2 completion
- Listed all deliverables with checkmarks
- Documented test results: 1062/1062 PASS

#### 3. Next Steps
- Clarified Phase 92 lowering requirements
- Updated timeline expectations

#### 4. Test Fixture Fix
- Fixed syntax error in test_pattern5b_escape_minimal.hako
  (field declarations: changed `console: ConsoleBox` to `console ConsoleBox`)

### Context

Phase 91 Step 2 is now fully complete:
- ✅ AST recognizer (detect_escape_skip_pattern)
- ✅ Canonicalizer integration (UpdateKind::ConditionalStep)
- ✅ Unit tests (test_escape_skip_pattern_recognition)
- ✅ Parity verification (strict mode green)

Ready for Phase 92 lowering implementation.

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

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

docs/development/current/main/phases/phase-91/README.md

@@ -1,9 +1,11 @@
 # Phase 91: JoinIR Coverage Expansion (Selfhost depth-2)
 
 ## Status
-- 🔍 **Analysis Complete**: Loop inventory across selfhost codebase
-- 📋 **Planning**: Pattern P5b (Escape Handling) candidate selected
-- ⏳ **Implementation**: Deferred to dedicated session
+- ✅ **Analysis Complete**: Loop inventory across selfhost codebase (Step 1)
+- ✅ **Planning Complete**: Pattern P5b (Escape Handling) candidate selected (Step 1)
+- ✅ **Implementation Complete**: AST recognizer, canonicalizer integration, unit tests (Step 2-A/B/D)
+- ✅ **Parity Verified**: Strict mode green in `test_pattern5b_escape_minimal.hako` (Step 2-E)
+- 📝 **Documentation**: Updated Phase 91 README with completion status
 
 ## Executive Summary
 
@@ -414,16 +416,30 @@ print(out)  // Should print: hello" world
 
 ---
 
+## Completion Status
+
+### Phase 91 Step 2: Implementation ✅ COMPLETE
+- ✅ Extended `UpdateKind` enum with `ConditionalStep` variant
+- ✅ Implemented `detect_escape_skip_pattern()` in AST recognizer
+- ✅ Updated canonicalizer to recognize P5b patterns
+- ✅ Added comprehensive unit test: `test_escape_skip_pattern_recognition`
+- ✅ Verified parity in strict mode (canonical vs actual decision routing)
+
+**Key Deliverables**:
+- Updated `skeleton_types.rs`: ConditionalStep support
+- Updated `ast_feature_extractor.rs`: P5b pattern detection
+- Updated `canonicalizer.rs`: P5b routing to Pattern2Break + unit test
+- Updated `test_pattern5b_escape_minimal.hako`: Fixed syntax errors
+
+**Test Results**: 1062/1062 tests PASS (including new P5b unit test)
+
+---
+
 ## Next Steps (Future Sessions)
 
-### Phase 91 Step 2: Implementation
-- Implement `detect_escape_pattern()` in Canonicalizer
-- Add unit tests for escape pattern recognition
-- Verify strict parity with router
-
 ### Phase 92: Lowering
-- Implement Pattern5bEscape lowerer
-- Handle variable-step carrier updates
+- Implement Pattern5bEscape lowerer in JoinIR
+- Handle ConditionalStep carrier updates with PHI composition
 - E2E test with `test_pattern5b_escape_minimal.hako`
 
 ### Phase 93: Pattern P5 (Guard-Bounded)

tools/selfhost/test_pattern5b_escape_minimal.hako

@@ -12,7 +12,7 @@
 // - Escape sequence handlers
 
 static box Main {
-    console: ConsoleBox
+    console ConsoleBox
 
     main() {
         me.console = new ConsoleBox()