feat: add dingtalk-feishu-collector SOP skill

Reusable 6-step pipeline for collecting DingTalk group messages,
extracting Feishu doc links, fetching content, and generating summaries.

Skills structure:
- SKILL.md: trigger rules, workflow, config reference
- config.yaml: group IDs, collection settings
- scripts/paths.py: shared path resolution
- scripts/step1-6: modular pipeline steps
- scripts/run_all.py: one-click runner

skills/dingtalk-feishu-collector/scripts/step4_download_files.py

@@ -0,0 +1,31 @@
+"""Step 4: 下载钉钉群文件附件"""
+import argparse, json, os, subprocess, sys
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+from paths import LINKS_DIR, DOWNLOAD_DIR, find_dws
+
+HTML_MD = {".html",".htm",".md",".markdown",".txt"}
+
+def main():
+    p = argparse.ArgumentParser(); p.add_argument("--incremental",action="store_true"); args = p.parse_args()
+    path = os.path.join(LINKS_DIR,"all_file_attachments.json")
+    if not os.path.isfile(path): print("ERROR: 先运行 step2"); sys.exit(1)
+    with open(path,"r",encoding="utf-8") as f: files = json.load(f)
+    print(f"附件: {len(files)} 个")
+    dws = find_dws()
+    new = 0
+    for fi in files:
+        fid, name = fi.get("fileId",""), fi.get("name","unknown")
+        if not fid: continue
+        ext = os.path.splitext(name)[1].lower()
+        subdir = "html-md" if ext in HTML_MD else "other"
+        out = os.path.join(DOWNLOAD_DIR, subdir)
+        os.makedirs(out, exist_ok=True)
+        print(f"  {name} -> {subdir}/")
+        try:
+            r = subprocess.run([dws,"drive","download","--node",fid,"--output",out],capture_output=True,timeout=120)
+            if r.returncode==0: new+=1
+            else: print(f"    FAIL")
+        except Exception as e: print(f"    ERR: {e}")
+    print(f"\n下载 {new} 个 -> {DOWNLOAD_DIR}")
+
+if __name__ == "__main__": main()