fix: remove the slack sync alias in favor of slack manifest sync

[zimeg]

Changelog

Removed the slack sync command alias. Use slack manifest sync instead.

Summary

This pull request removes the top-level slack sync alias in favor of slack manifest sync.

• Drops the "sync" entry from AliasMap in cmd/root.go.
• Regenerates command docs: removes the slack sync index entry and deletes the orphaned slack_sync.md reference page.
• The slack manifest sync command itself is unchanged and remains the single way to sync a manifest between the local project and app settings.

Preview

N/A — CLI-only change.

Testing

• Run ./bin/slack sync and confirm it reports unknown command "sync" for "slack".
• Run ./bin/slack manifest sync --help and confirm the command still works as before.

Notes

slack manifest sync covers this workflow, so the shortcut alias is no longer needed.

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.20%. Comparing base (fcb0782) to head (ed38f06).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #674      +/-   ##
==========================================
+ Coverage   78.19%   78.20%   +0.01%     
==========================================
  Files         239      239              
  Lines       18132    18132              
==========================================
+ Hits        14178    14181       +3     
+ Misses       3954     3951       -3     

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[zimeg]

🗣️ Conversations admist release hint that the shortcut is best so I close this change:

$ slack sync