feat(ack): bind test env to deployer and add regression mode

ACK 0.19.0 hands test-environment deploys to the deployer skill,
documents bug-fix as a first-class scenario, and adds
docs/ack/regression.yaml harvest plus a /ack regression run.

skills/ack/templates/tasks.template.yaml

@@ -9,6 +9,7 @@ project:
   overlayFile: "docs/ack/project.md"
   knowledgeFile: "docs/ack/knowledge.yaml"
   deliveryFile: "docs/ack/delivery.yaml"
+  regressionFile: "docs/ack/regression.yaml"
   # 可选：飞书 Base Bug 收件箱。只保存 profile 名和资源 ID，绝不保存 App Secret。
   # bugIntake:
   #   provider: "feishu-base"
@@ -114,6 +115,7 @@ project:
 
 workerReceipts: []
 deliveryRuns: []
+regressionRuns: []
 
 summary:
   verified: []
@@ -137,6 +139,8 @@ tasks:
     knowledgeApplied: []
     knowledgeCandidates: []
     knowledgeChecks: []
+    regressionRefs: []
+    regressionCandidates: []
 
     # 从飞书导入时由 Coordinator 写入；source.ref 是幂等键。
     # source: