fix(cli): point bm cloud setup hint at bm cloud sync-setup

[groksrc]

Summary

• bm cloud setup printed bm project sync-setup ... in its "Next steps", but the command is registered under the cloud Typer app (@cloud_app.command("sync-setup") in cli/commands/cloud/project_sync.py:275). Following the hint produced No such command 'sync-setup'.
• Replaced the bad command in the post-setup output (cli/commands/cloud/core_commands.py:182) and in docs/cloud-cli.md (4 occurrences) with the correct bm cloud sync-setup.

Closes #779

Test plan

• bm cloud setup "Next steps" output now shows bm cloud sync-setup <name> <path>
• bm cloud sync-setup --help resolves (sanity check the command path is unchanged)
• docs/cloud-cli.md no longer references bm project sync-setup

🤖 Generated with Claude Code

[github-actions]

Claude finished @groksrc's task in 1m 17s —— View job

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Code Review

• Gather context and read changed files
• Verify the fix is correct
• Run through team checklist

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Summary: This is a clean, minimal, correct fix. The command sync-setup is registered under @cloud_app.command("sync-setup") at cli/commands/cloud/project_sync.py:275, confirming bm cloud sync-setup is the correct invocation. No remaining incorrect bm project sync-setup references were found after the fix.

Team Checklist

Code Quality & Standards

• Follows Basic Memory's coding conventions — pure string/doc change, no logic altered
• Line length — changed line at core_commands.py:182 is well within 100 chars
• No commented-out code blocks

Testing & Documentation

• No new functions/logic — no tests required for a hint text fix
• Documentation updated — all 4 occurrences in docs/cloud-cli.md corrected
• CLAUDE.md update not required

Basic Memory Architecture

• N/A — no architectural changes

Security & Performance

• No concerns

Compatibility

• No emojis or unicode added
• No Windows path concerns

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Verdict: LGTM ✓ — The root cause (wrong namespace in the hint) is correctly diagnosed and fully fixed in both the CLI output and the docs. The PR is appropriately scoped with no unrelated changes.

Note (out of scope for this PR): While reviewing, I noticed docs/cloud-cli.md also references bm project sync (e.g. lines 294, 303, 730) — but sync is also registered under @cloud_app.command("sync") at project_sync.py:92. Worth a follow-up issue to check if those references also need correcting.