docs: normalize frontmatter titles to sentence case

docs/help/environment.md

@@ -4,7 +4,7 @@ read_when:
   - You need to know which env vars are loaded, and in what order
   - You are debugging missing API keys in the Gateway
   - You are documenting provider auth or deployment environments
-title: "Environment Variables"
+title: "Environment variables"
 ---
 
 OpenClaw pulls environment variables from multiple sources. The rule is **never override existing values**.

docs/help/gpt54-codex-agentic-parity-maintainers.md

@@ -1,5 +1,5 @@
 ---
-title: "GPT-5.4 / Codex Parity Maintainer Notes"
+title: "GPT-5.4 / Codex parity maintainer notes"
 summary: "How to review the GPT-5.4 / Codex parity program as four merge units"
 read_when:
   - Reviewing the GPT-5.4 / Codex parity PR series

docs/help/gpt54-codex-agentic-parity.md

@@ -1,5 +1,5 @@
 ---
-title: "GPT-5.4 / Codex Agentic Parity"
+title: "GPT-5.4 / Codex agentic parity"
 summary: "How OpenClaw closes agentic execution gaps for GPT-5.4 and Codex-style models"
 read_when:
   - Debugging GPT-5.4 or Codex agent behavior

docs/help/troubleshooting.md

@@ -3,7 +3,7 @@ summary: "Symptom first troubleshooting hub for OpenClaw"
 read_when:
   - OpenClaw is not working and you need the fastest path to a fix
   - You want a triage flow before diving into deep runbooks
-title: "General Troubleshooting"
+title: "General troubleshooting"
 ---
 
 # Troubleshooting