docs(joinir): Phase 189 JsonParser mini verification

Investigation Results:
- _match_literal: ✅ Works correctly (Pattern1)
- _parse_number: ❌ Blocked by LoopBodyLocal
- _atoi: ❌ Carrier detection gap identified

Root Cause: Carrier Detection Limitation
- Pattern1/2 only detect loop counter from condition
- Accumulator variables (result = result * 10 + digit) not detected
- MIR shows missing PHI for accumulator variables

Phase 188 Status:
- StringAppend implementation: ✅ Complete and correct
- End-to-end verification: ⏳ Waiting for carrier detection fix

Phase 190 Options:
- Option A: Expand LoopUpdateAnalyzer (recursive traversal)
- Option B: Explicit carrier annotation syntax
- Option C: Whole-body variable analysis

Created:
- phase189-jsonparser-mini-verification.md (comprehensive report)
- 3 test files (parse_number, atoi, match_literal)

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

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

apps/tests/phase189_atoi_mini.hako

@@ -0,0 +1,15 @@
+// Phase 189: Minimal test for _atoi pattern
+// Expected behavior: StringAppend-style loop with early break
+
+static box Atoi {
+  method main() {
+    local result = 0
+    local i = 0
+    loop(i < 3) {
+      if i >= 2 { break }
+      result = result * 10 + i
+      i = i + 1
+    }
+    print(result)  // Expected: 01 -> 1 (0*10+0=0, 0*10+1=1, then break)
+  }
+}

apps/tests/phase189_match_literal_mini.hako

@@ -0,0 +1,14 @@
+// Phase 189: Minimal test for _match_literal pattern
+// Expected behavior: Simple loop with conditional break
+
+static box MatchLiteral {
+  method main() {
+    local matched = 0
+    local i = 0
+    loop(i < 3) {
+      if i == 2 { matched = 1; break }
+      i = i + 1
+    }
+    print(matched)  // Expected: 1 (matched when i==2)
+  }
+}

apps/tests/phase189_parse_number_mini.hako

@@ -0,0 +1,15 @@
+// Phase 189: Minimal test for _parse_number pattern
+// Expected behavior: StringAppend-style loop with accumulator
+
+static box ParseNumber {
+  method main() {
+    local num = 0
+    local i = 0
+    loop(i < 3) {
+      local digit = i  // Simplified digit extraction
+      num = num * 10 + digit
+      i = i + 1
+    }
+    print(num)  // Expected: 012 -> 12 (0*10+0=0, 0*10+1=1, 1*10+2=12)
+  }
+}