Refactor: Replace deprecated Flutter APIs across the project

[Satyanarayana001]

The project currently uses several deprecated Flutter APIs that generate warnings during analysis.

Examples include:

• withOpacity() → deprecated, should use withValues(alpha: ...)
• surfaceVariant → replaced by surfaceContainerHighest
• Deprecated drag callbacks (onAccept, onWillAccept)
• Deprecated speech recognition parameters

These deprecations may lead to compatibility issues with newer Flutter versions.

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🎯 Proposed Changes

• Replace all usages of withOpacity() with withValues(alpha: ...)
• Update surfaceVariant to surfaceContainerHighest
• Migrate deprecated drag-and-drop callbacks
• Update speech recognition API usage

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✅ Benefits

• Reduces analyzer warnings
• Improves codebase maintainability
• Ensures compatibility with latest Flutter versions

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📊 Additional Context

Running flutter analyze shows multiple deprecation warnings across different modules. :contentReference[oaicite:0]{index=0}

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🙋‍♂️ Contribution

I would like to work on this issue.

[Satyanarayana001]

I have identified multiple occurrences and will submit a PR addressing these changes soon.

[Salman46-git]

hlo! i am @Salman46
Issue: Migrate Deprecated Flutter APIs for Better Compatibility

The project currently relies on several deprecated Flutter APIs that trigger warnings during static analysis. While the application may continue functioning for now, these APIs are scheduled for removal or replacement in newer Flutter releases and may introduce future compatibility or maintenance issue.

Current Deprecations Identified

Examples found during analysis include:

withOpacity() → deprecated, replace with withValues(alpha: ...)
surfaceVariant → replaced by surfaceContainerHighest
Deprecated drag-and-drop callbacks:
onAccept
onWillAccept
Deprecated speech recognition parameters and APIs

Proposed Changes

Replace all withOpacity() usages with withValues(alpha: ...)
Migrate surfaceVariant to surfaceContainerHighest
Update deprecated drag-and-drop callback implementations to the recommended alternatives
Refactor speech recognition API usage to align with the latest Flutter/plugin standards

/assign me