[Task](docs): create and include Forms pattern docs

[franzheidl]

Currently, there is no place for properly documenting Forms patterns int he current docs structure.

Create the content, and include it in the structure and TOC.

Forms Pattern Content – Outline:

Forms

1. When to use a form
   Inline form vs. modal form vs. dedicated form page — when each is appropriate
   Reference to the Modals doc for modal-specific guidance
2. Form layout
   Single-column vs. two-column layouts
   Field ordering — logical grouping, progressive disclosure
   Required vs. optional fields — labelling conventions
3. Validation
   When to validate — on blur, on submit, or inline as-you-type; pros/cons of each
   Inline field errors vs. summary errors at the top — when to use which
   Cross-field validation (e.g. "password must match")
   Reference to error-handling-loading-empty-states.md for error message wording
4. Conditional and dependent fields
   Showing/hiding fields based on other field values
   Keeping hidden field state when fields reappear
5. Submit and cancel actions
   Button placement and order (primary action, cancel)
   Disabling submit until valid — when this helps vs. hurts
   Destructive submit actions — confirmation strategies
   Reference to ux-writing-content-design.md for button labels
6. Submission feedback
   Success: what to show after a successful submit (in-page message, navigation, inline confirmation)
   In-progress: busy/loading state on the submit button
   Failure: server-side errors vs. validation errors — how to surface them
   Reference to messages-and-notifications.md

Forms Pattern in the Current Structure of Our Docs

Add Forms (or find a better, more descriptive title) as a second level item under UX Patterns/iv. Forms, effectivley shifting Wizard Pattern to v.