feat(tasks): add skill-templated task graph execution

app-instance/backend/beaver/skills/catalog/utils.py

@@ -17,6 +17,7 @@ import json
 import os
 import re
 import shutil
+from dataclasses import dataclass, field
 from typing import Any
 
 
@@ -84,6 +85,27 @@ def strip_frontmatter(content: str) -> str:
     return body
 
 
+@dataclass(slots=True)
+class SkillTeamTemplateParseResult:
+    template: dict[str, Any] | None = None
+    warnings: list[str] = field(default_factory=list)
+
+
+def extract_skill_team_template(body: str) -> SkillTeamTemplateParseResult:
+    matches = re.findall(r"```beaver-team-template\s*\n(.*?)\n```", body, re.DOTALL)
+    if not matches:
+        return SkillTeamTemplateParseResult()
+    if len(matches) != 1:
+        return SkillTeamTemplateParseResult(warnings=["skill defines multiple team templates"])
+    try:
+        template = json.loads(matches[0])
+    except json.JSONDecodeError:
+        return SkillTeamTemplateParseResult(warnings=["team template JSON is invalid"])
+    if not isinstance(template, dict) or not isinstance(template.get("nodes", []), list):
+        return SkillTeamTemplateParseResult(warnings=["team template must be an object with a nodes list"])
+    return SkillTeamTemplateParseResult(template=template)
+
+
 def extract_required_tool_names(body: str) -> list[str]:
     """从 canonical skill 正文的 `## Required Tools` 段落提取工具名。