JadxPlus: Insufficient input validation in SpecsJadx.decompileAPK()

[lm-sousa]

Bug Description:
The SpecsJadx.decompileAPK() methods appear to lack sufficient input validation for APK files, allowing empty or malformed files to be processed without appropriate error handling.

Impact:
Could lead to undefined behavior, resource waste, or misleading success indicators for invalid operations.

Recommendation:
Implement proper APK file validation including file size checks, magic number verification, and basic structure validation.

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This issue was identified by Copilot and needs human review.