🎨 Palette: Enhance button semantics and input accessibility

[myarichuk]

The application contained several minor accessibility and UX issues in its Blazor UI:

1. Accessibility (a11y) Issue: The search <input> in Players.razor relied entirely on the placeholder attribute to provide context, missing an explicit <label> or aria-label. This makes the field inaccessible or confusing for screen reader users.
2. Semantic Issue: Numerous interactive clickable UI elements across Home.razor, Grimoire.razor, and Players.razor were implemented as <button> tags without an explicit type attribute. In HTML, <button> defaults to type="submit", which can cause unintended side effects (like accidental page reloads) if these buttons are ever wrapped inside a <form> element.

This PR addresses both issues:

• Added aria-label="Search players or characters..." to the search input in Players.razor.
• Added type="button" to dozens of interactive buttons (add, delete, analyze, dismiss, generate, etc.) across Players.razor, Home.razor, and Grimoire.razor to enforce correct semantic behavior.
• Documented the learning regarding placeholder-only inputs in .Jules/palette.md.

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PR created automatically by Jules for task 16099775094637351108 started by @myarichuk

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