docs: encourage batch close and parallel creation in bd prime output

- Update examples to show `bd close <id1> <id2> ...` for batch closing
- Add quick reference entry for closing multiple issues at once
- Add tip about using parallel subagents for creating multiple issues
- Add comment in example about running bd create in parallel

Cherry-picked from PR #452 (prime.go changes only)

Co-Authored-By: Ryan Snodgrass <rsnodgrass@gmail.com>

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

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

cmd/bd/prime.go

@@ -167,8 +167,8 @@ func outputCLIContext() error {
 - ` + "`bd sync --status`" + ` - Check sync status without syncing`
 		completingWorkflow = `**Completing work:**
 ` + "```bash" + `
-bd close <id>           # Mark done
-bd sync --from-main     # Pull latest beads from main
+bd close <id1> <id2> ...    # Close all completed issues at once
+bd sync --from-main         # Pull latest beads from main
 git add . && git commit -m "..."  # Commit your changes
 # Merge to main when ready (local merge, not push)
 ` + "```"
@@ -185,8 +185,8 @@ git add . && git commit -m "..."  # Commit your changes
 - ` + "`bd sync --status`" + ` - Check sync status without syncing`
 		completingWorkflow = `**Completing work:**
 ` + "```bash" + `
-bd close <id>      # Mark done
-bd sync            # Push to remote
+bd close <id1> <id2> ...    # Close all completed issues at once
+bd sync                     # Push to remote
 ` + "```"
 	}
 
@@ -224,7 +224,9 @@ bd sync            # Push to remote
 - ` + "`bd update <id> --status=in_progress`" + ` - Claim work
 - ` + "`bd update <id> --assignee=username`" + ` - Assign to someone
 - ` + "`bd close <id>`" + ` - Mark complete
+- ` + "`bd close <id1> <id2> ...`" + ` - Close multiple issues at once (more efficient)
 - ` + "`bd close <id> --reason=\"explanation\"`" + ` - Close with reason
+- **Tip**: When creating multiple issues/tasks/epics, use parallel subagents for efficiency
 
 ### Dependencies & Blocking
 - ` + "`bd dep add <issue> <depends-on>`" + ` - Add dependency (issue depends on depends-on)
@@ -250,6 +252,7 @@ bd update <id> --status=in_progress  # Claim it
 
 **Creating dependent work:**
 ` + "```bash" + `
+# Run bd create commands in parallel (use subagents for many items)
 bd create --title="Implement feature X" --type=feature
 bd create --title="Write tests for X" --type=task
 bd dep add beads-yyy beads-xxx  # Tests depend on Feature (Feature blocks tests)