docs: update CHANGELOG, README, GUI changelog for v3.8.0 AI Monitoring

- CHANGELOG.md: full v3.8.0 section with 3-tier system, 30 fault types, safety guards
- README.md: AI Monitoring badge, features section, Phase 9 dev journey, troubleshooting rows
- GUI CHANGELOG: v3.8.0 entry with 9 bullet points

src/codex-launcher-gui

@@ -26,6 +26,17 @@ model_catalog_json = ""
 """
 
 CHANGELOG = [
+    ("3.8.0", "2026-05-22", [
+        "AI Monitoring — self-healing watchdog with 3-tier response system",
+        "HealthWatcher: monitors proxy health every 5s, auto-restarts on crash",
+        "LogAnalyzer: tails debug logs for 18 failure signal patterns",
+        "Tier 1: 14 rule-based auto-recovery rules (< 1s response)",
+        "Tier 2: Incident pattern store with success rate tracking",
+        "Tier 3: AI diagnostic agent — configurable provider/model for novel failures",
+        "30 fault types catalogued across 5 categories (A-E)",
+        "GUI: AI Monitor panel with ON/OFF, provider selector, incident log",
+        "Enhanced /health endpoint with memory and uptime metrics",
+    ]),
     ("3.7.0", "2026-05-22", [
         "Intelligence Routing — self-healing parser system for Command Code",
         "Layer 1: Deep URL extraction from nested JSON in explore_agent blocks",