Gui: redesign Macros dialog layout for clarity

[dragonfruit-blue]

Summary

• Renames the dialog title from "Execute Macro" to "Macros" to better reflect its full scope (execute, create, edit, rename, duplicate, delete, toolbar setup, download)
• Removes the confusing "Macro Name" group box wrapper; replaces it with a clean "Selected:" label row below the macro list
• Moves search fields ("Find file" / "Find in files") to a dedicated top row, no longer buried inside a group box
• Reorganizes the button column into logical groups separated by visible divider lines:
  • Execute (primary action, at top)
  • Create / Edit / Rename / Duplicate / Delete (file management)
  • Toolbar / Download (secondary actions)
  • Close (bottom)
• Fixes tab bar label clipping by enforcing a minimum width per tab

No .cpp changes — all widget object names are preserved, so all existing signal/slot connections and logic remain intact.

Test plan

• Open Macro menu → Macros... and verify dialog title shows "Macros"
• Verify both "User macros" and "System macros" tab labels are fully visible
• Verify separator lines are visible between button groups
• Verify Execute, Edit, Delete, Rename, Duplicate, Toolbar buttons enable/disable correctly on selection
• Verify double-clicking a macro executes it
• Verify Create, Rename, Duplicate, Delete operations work correctly
• Verify Toolbar walkthrough and Download (Addon Manager) buttons work
• Verify User Macros Location path chooser and Open Folder button work

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