Brand Posting Defaults

✨ New Features

• Posting Defaults Per Brand: Save defaults per brand (word count, quality, images, research, etc.). They apply when you start a new draft.
• Posting Defaults Dialog: Edit them from a dedicated dialog on each brand card (Switch · View · Posting defaults).
• Deep Link to Defaults: Jump from a draft straight into editing that brand’s posting defaults.

🧹 Improvements

• Draft Empty State: No defaults yet? You get “Set up defaults for {brand}” instead of a disabled toggle that looked broken.
• Save Closes the Dialog: Saving posting defaults closes the dialog so it feels saved.