🎨 Palette: Improve screen reader navigation and reduce noise in camera layout

[manupawickramasinghe]

💡 What:

• Added accessibilityHeading="true" to the main app title (@id/textView).
• Added importantForAccessibility="no" to the camera preview surface (@id/view_finder).

🎯 Why:

• Headings provide critical structural landmarks for screen reader users, allowing them to quickly jump through the UI rather than swiping sequentially through every element.
• The camera surface view announces as "Unlabeled" and provides no context to visually impaired users. Hiding it reduces noise and improves the overall experience when opening the app.

♿ Accessibility:

• Improves heading navigation support for TalkBack.
• Reduces cognitive load and unnecessary announcements by hiding purely visual/decorative views from the accessibility tree.

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PR created automatically by Jules for task 13761189702996126001 started by @manupawickramasinghe

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