chore: import SiteForge Factory V5 source (baseline)

导入 SiteForge Factory V5 基线源码：
- FastAPI + SQLite + Docker Compose（Web + Worker）架构
- 四套商业主题 × 14 页面模板（1.1.0，含历史版本快照）
- 四种建站模式骨架 + 迁移审计 + 发布门禁
- 52 项 pytest 测试
- 补全计划主文档 docs/superpowers/plans/

Co-Authored-By: Claude Code <noreply@anthropic.com>

app/worker.py

@@ -0,0 +1,60 @@
+"""Dedicated Docker worker: database-backed queue, serialized claim, retry + restart recovery."""
+import json
+import os
+import signal
+import time
+from datetime import datetime, timedelta, timezone
+from . import db, enterprise, builder
+
+running=True
+
+def stop(*_):
+    global running
+    running=False
+
+def claim():
+    with db.connect() as c:
+        c.execute('BEGIN IMMEDIATE')
+        job=c.execute("""SELECT id FROM build_jobs
+            WHERE state='queued' AND (retry_at IS NULL OR retry_at<=?)
+            ORDER BY created_at,id LIMIT 1""",(db.now(),)).fetchone()
+        if not job:return None
+        c.execute("UPDATE build_jobs SET state='running',attempts=attempts+1,started_at=?,retry_at=NULL WHERE id=?",(db.now(),job['id']))
+        return dict(c.execute('SELECT * FROM build_jobs WHERE id=?',(job['id'],)).fetchone())
+
+def run_once():
+    job=claim()
+    if job is None:return None
+    try:
+        if job['kind']=='build': result=builder.build(job['site_id'],False)
+        else:raise ValueError('Unsupported job')
+        db.execute("UPDATE build_jobs SET state='done',result_json=?,finished_at=? WHERE id=?",
+            (json.dumps(result,ensure_ascii=False),db.now(),job['id']))
+    except Exception as exc:
+        maximum=max(1,int(os.getenv('SITEFORGE_JOB_MAX_ATTEMPTS','3')))
+        if job['attempts']<maximum:
+            delay=min(300,5*(2**max(job['attempts']-1,0)))
+            retry_at=(datetime.now(timezone.utc)+timedelta(seconds=delay)).isoformat(timespec='seconds')
+            db.execute("""UPDATE build_jobs SET state='queued',error=?,started_at=NULL,
+                       finished_at=NULL,retry_at=? WHERE id=?""",
+                       (str(exc)[:1200],retry_at,job['id']))
+        else:
+            db.execute("UPDATE build_jobs SET state='failed',error=?,finished_at=?,retry_at=NULL WHERE id=?",
+                       (str(exc)[:1200],db.now(),job['id']))
+    return job['id']
+
+def main():
+    db.init();enterprise.setup()
+    signal.signal(signal.SIGTERM,stop);signal.signal(signal.SIGINT,stop)
+    # A crash before the build record is committed is safe to retry: build IDs
+    # are generated inside builder.build and output directories are immutable.
+    maximum=max(1,int(os.getenv('SITEFORGE_JOB_MAX_ATTEMPTS','3')))
+    db.execute("""UPDATE build_jobs SET state='queued',error='Worker interrupted; retry scheduled',
+               started_at=NULL,finished_at=NULL,retry_at=?
+               WHERE state='running' AND attempts<?""",(db.now(),maximum))
+    db.execute("""UPDATE build_jobs SET state='failed',error='Worker interrupted; retry limit reached',
+               finished_at=?,retry_at=NULL WHERE state='running'""",(db.now(),))
+    while running:
+        if not run_once():time.sleep(float(os.getenv('SITEFORGE_JOB_POLL_SECONDS','1.5')))
+
+if __name__=='__main__':main()