fix: polish widget edit & preview screens

[jvsena42]

Description

This PR:

1. Removes the Show Widget Titles setting end-to-end
2. Removes the legacy description text from the widget edit screens
3. Restyles the Blocks widget edit rows to match Figma v61
4. Adds a divider to the Facts widget preview screen

A set of small follow-up fixes on top of the widgets foundation work, bringing the iOS widget screens in line with Figma v61 and the equivalent Android polish.

The Show Widget Titles setting is removed from the Widgets settings screen and its underlying storage, backup config, and migration mapping. The widget title header (icon + name) now shows only while editing the dashboard, which matches the previous default behavior. Existing persisted values are ignored safely on read.

The widget edit screens no longer show the legacy description paragraph above the options. The Blocks edit rows now use the correct text styles and colors per Figma: regular labels at 80% white and semibold values in full white. The Facts preview screen gains a divider below its description, consistent with the other widget preview screens.

Linked Issues/Tasks

N/A

Screenshot / Video

Simulator.Screen.Recording.-.iPhone.16.-.2026-05-21.at.19.43.15.mp4

QA Notes

Manual Tests

• 1. Settings → Widgets: no "Show Widget Titles" toggle is shown.
• 2. Blocks widget → edit: row labels render regular at 80% white, values semibold in full white, icons orange, checkboxes orange when selected / gray when not.
• 3. Facts widget → preview: a divider appears below the description.

Automated Checks

• N/A — copy, color, layout, and dead-code removal only; no automated coverage added or changed. SwiftFormat run locally on the touched files.