refactor(workflow): rename workflow-lite-plan to workflow-lite-planex and remove standalone lite-execute

- Rename skill directory from workflow-lite-plan to workflow-lite-planex (planex = plan + execute)
- Remove standalone lite-execute command entry from command.json and analyze_commands.py
- Update all 60+ files referencing workflow-lite-plan to use workflow-lite-planex
- Update descriptions to clarify Phase 1: plan → Phase 2: execute architecture
- Remove lite-execute as standalone command from orchestrator routing tables
- Update docs (EN/ZH) to reflect unified planex naming and phase descriptions

.claude/skills/spec-generator/phases/06-readiness-check.md

@@ -210,7 +210,7 @@ AskUserQuestion({
       options: [
         {
           label: "Execute via lite-plan",
-          description: "Start implementing with /workflow-lite-plan, one Epic at a time"
+          description: "Start implementing with /workflow-lite-planex, one Epic at a time"
         },
         {
           label: "Create roadmap",
@@ -242,7 +242,7 @@ if (selection === "Execute via lite-plan") {
   const epicContent = Read(firstMvpFile);
   const title = extractTitle(epicContent);       // First # heading
   const description = extractSection(epicContent, "Description");
-  Skill(skill="workflow-lite-plan", args=`"${title}: ${description}"`)
+  Skill(skill="workflow-lite-planex", args=`"${title}: ${description}"`)
 }
 
 if (selection === "Full planning" || selection === "Create roadmap") {