Add paragraph line spacing controls in style settings

Feature Request: Add paragraph line spacing controls in style settings

Summary:
Introduce configurable paragraph line spacing options within the style settings so users can define and apply consistent spacing (e.g., single, 1.15, 1.5, double) across their documents. This will make it easier to maintain readable, standardized formatting without manually adjusting spacing for each paragraph.

Problem Statement:
Currently, users have limited or no direct control over paragraph line spacing through styles. To achieve specific spacing, they must either rely on default behavior or manually tweak formatting paragraph by paragraph. This is time-consuming, inconsistent across documents, and makes it difficult to enforce formatting standards—especially in longer documents or when multiple collaborators are involved.

Proposed Solution:
Add a dedicated “Paragraph Line Spacing” setting within the existing style or formatting panel.
Allow users to choose from common presets (e.g., 1.0, 1.15, 1.5, 2.0) and, optionally, define a custom value.
Ensure that line spacing can be saved as part of a named style (e.g., “Body text,” “Heading,” “Caption”) so that applying a style automatically applies the correct spacing.
Support updating existing content: when a style’s line spacing is changed, all paragraphs using that style should update accordingly.
Provide a simple preview (e.g., sample text in the style panel) so users can see how the chosen spacing will look before applying it document-wide.

Benefits:
Improves readability and visual consistency of documents by enforcing standard paragraph spacing.
Reduces manual effort and formatting time, especially for longer or frequently updated documents.
Enables teams to define and reuse house styles that include precise spacing rules.
Decreases formatting errors and inconsistencies across collaborators and versions.
Enhances overall user satisfaction by giving more precise control over document appearance.