feat: add /workflow:session:sync command and integrate auto-sync into execution pipelines

Add a new session sync command that updates both project-guidelines.json
and project-tech.json from session context in one shot. Replace inline
Step 6 (Update Development Index) in lite-execute with sync call, and
add auto-sync to Post-Completion Expansion across 6 execution commands.
Simplify session/complete by replacing Phase 4+5 with single sync call.

.claude/skills/workflow-test-fix/SKILL.md

@@ -396,6 +396,8 @@ Automatic commits at key checkpoints:
 
 ## Post-Completion Expansion
 
+**Auto-sync**: Execute `/workflow:session:sync -y "{summary}"` to update project-guidelines + project-tech.
+
 After completion, ask user if they want to expand into issues (test/enhance/refactor/doc). Selected items call `/issue:new "{summary} - {dimension}"`.
 
 ## Coordinator Checklist

.claude/skills/workflow-test-fix/phases/05-test-cycle-execute.md

@@ -454,6 +454,8 @@ The orchestrator automatically creates git commits at key checkpoints to enable
 
 #### Post-Completion Expansion
 
+**Auto-sync**: 执行 `/workflow:session:sync -y "{summary}"` 更新 project-guidelines + project-tech。
+
 完成后询问用户是否扩展为issue(test/enhance/refactor/doc)，选中项调用 `/issue:new "{summary} - {dimension}"`
 
 ## Agent Roles Summary