fix(docs): standardize sync branch name and daemon syntax (GH#376)

- Replace beads-metadata with beads-sync throughout docs
  (matches code default and internal examples)
- Fix bd daemon start → bd daemon --start (correct flag syntax)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/QUICKSTART.md

@@ -25,7 +25,7 @@ bd init --contributor
 bd init --team
 
 # Protected main branch (GitHub/GitLab)
-bd init --branch beads-metadata
+bd init --branch beads-sync
 ```
 
 The wizard will: