Address 503 lint errors and 914 warnings

[callebtc]

Description:
Android Lint detected a massive number of issues:

• 503 errors
• 914 warnings

These could include security vulnerabilities, performance issues, and compatibility problems.

Current Status:
Build succeeds despite errors due to abortOnError = false in build.gradle.

Investigation Required:

1. Generate detailed lint report: ./gradlew lintDebug
2. Review HTML report at: app/build/reports/lint-results-debug.html
3. Prioritize fixing:
   • Security issues (highest priority)
   • Performance issues
   • API compatibility issues
   • Accessibility issues

Fix Instructions:

1. Run lint analysis: ./gradlew lintDebug
2. Open the generated HTML report
3. Fix issues by category, starting with highest severity
4. Consider enabling abortOnError = true once critical issues are resolved

Note: This is a meta-issue that may spawn additional specific issues based on lint findings.