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>

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()