fix: clairify the helptext that markdown is supported with a warning about HTML indentation

[iyawnnn]

Description

Fixes #6180

This PR adds a help text to the "Description" and "Footer Text" fields in the Status Page edit screen. It warns users that adding leading spaces to HTML content will cause formatting issues (due to the Markdown parser interpreting indentation as code blocks).

Changes

• UI Update: Added a warning message below the Description and Footer Text text areas in src/pages/StatusPage.vue.
• Localization: Added the htmlIndentationWarning key to src/lang/en.json to ensure the text is translatable.

Reasoning

Users frequently paste indented HTML into these fields, which causes the content to be rendered as a code block or with broken formatting due to Markdown rules. This help text clarifies the behavior directly in the UI.

Type of change

• Enhancement (non-breaking change which improves UX)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas

[CommanderStorm]

Please change markdownSupported instead of adding a new translation key for this.
It is much simpler to translate this way, especially for RTL languages.

[CommanderStorm]

Thank you, LGTM