feat: rename skills/skiff to pouch and move ACK state under .pouch

Use ~/.pouch, the pouch CLI, and .pouch.yaml as the SSOT container.
Keep the inner skills/ packages, and store ACK project state in
.pouch/ack instead of docs/ack.

skills/builder/README.md

@@ -47,5 +47,5 @@ DOCKER_REGISTRY=registry.example.com
 | `scripts/publish_docker.sh` | buildx 构建 + 推送镜像，远端 digest 验证 |
 | `scripts/verify_deb.sh` | 核对包元数据、内容与 SHA-256 |
 
-环境变量契约、脚本解析顺序（`$BUILDER_SKILL_DIR` → `~/.skills/skills/builder/scripts/`）、
+环境变量契约、脚本解析顺序（`$BUILDER_SKILL_DIR` → `~/.pouch/skills/builder/scripts/`）、
 脏工作树策略等完整规则见 contract.md。

skills/builder/references/contract.md

@@ -81,10 +81,10 @@ Agent 只保留授权判断和歧义处理。**
 push 目标定位 builder 脚本时按以下顺序，命中即用，不做静默兜底：
 
 1. `$BUILDER_SKILL_DIR/scripts/`（特殊安装位置）
-2. `$HOME/.skills/skills/builder/scripts/`（标准 clone 位）
+2. `$HOME/.pouch/skills/builder/scripts/`（标准 clone 位）
 
-两个位置都不可用时必须失败并提示：设置 `BUILDER_SKILL_DIR`，或把 skills 仓库
-clone 到 `~/.skills`。
+两个位置都不可用时必须失败并提示：设置 `BUILDER_SKILL_DIR`，或把 pouch 仓库
+clone 到 `~/.pouch`。
 
 ## 5. 校验
 

skills/builder/scripts/check.py

@@ -196,7 +196,16 @@ def check_docker_recipe(report: Report, project: Path) -> None:
 
 SCRIPT_RESOLVE_SNIPPETS = tuple(
     f"{prefix}{name}"
-    for prefix in ("$$BUILDER_SKILL_DIR", "$BUILDER_SKILL_DIR", "$$HOME/.skills/skills/builder/scripts", "$HOME/.skills/skills/builder/scripts", "~/.skills/skills/builder/scripts")
+    for prefix in (
+        "$$BUILDER_SKILL_DIR",
+        "$BUILDER_SKILL_DIR",
+        "$$HOME/.pouch/skills/builder/scripts",
+        "$HOME/.pouch/skills/builder/scripts",
+        "~/.pouch/skills/builder/scripts",
+        "$$HOME/.skills/skills/builder/scripts",
+        "$HOME/.skills/skills/builder/scripts",
+        "~/.skills/skills/builder/scripts",
+    )
     for name in VALID_SCRIPT_NAMES
 )
 
@@ -218,7 +227,7 @@ def check_push_delegates(report: Report, project: Path, dual_artifact: bool) ->
         elif not any(snippet in text for snippet in SCRIPT_RESOLVE_SNIPPETS) \
                 and "$(BUILDER_SCRIPT)" not in text and "upload_deb.sh" not in text \
                 and "publish_docker.sh" not in text:
-            inline.append(f"{target}: does not call a builder script (expected $BUILDER_SKILL_DIR/... or ~/.skills/... path)")
+            inline.append(f"{target}: does not call a builder script (expected $BUILDER_SKILL_DIR/... or ~/.pouch/... path)")
         else:
             thin.append(target)
     problems = []
@@ -262,6 +271,7 @@ def check_script_paths(report: Report) -> None:
     if env_dir:
         candidates.append(Path(env_dir) / "scripts")
     home = Path(os.environ.get("HOME", ""))
+    candidates.append(home / ".pouch" / "skills" / "builder" / "scripts")
     candidates.append(home / ".skills" / "skills" / "builder" / "scripts")
     found = next((c for c in candidates if c.is_dir() and any((c / n).is_file() for n in VALID_SCRIPT_NAMES)), None)
     if found:
@@ -270,7 +280,7 @@ def check_script_paths(report: Report) -> None:
         report.add(FAIL, 9, "builder 脚本路径可达", "\n".join([
             "none of these resolve to scripts/upload_deb.sh:",
             *(f"  {c}" for c in candidates),
-            "Fix: set BUILDER_SKILL_DIR, or clone the skills repo to ~/.skills.",
+            "Fix: set BUILDER_SKILL_DIR, or clone the pouch repo to ~/.pouch.",
         ]))