Subscribe form upgrades and builder polish

• Added subscribe form notice text with rich text support and an optional consent checkbox.

• Improved form styling inside content areas, including better button alignment for form layouts.

• Improved heading wrapping with balanced text and applied the theme accent color to native form controls for more consistent output.

• Fixed search block alignment issues in rendered layouts.

• Fixed stacked author image presentation on post cards and post pages.

• Fixed untranslated interface strings, the mobile menu logo focus outline, and section card column visibility when background images are enabled.