fix: prefer std::filesystem error_code overloads over exceptions

[hesam-oxe]

Replaced throwing std::filesystem calls with non-throwing error_code
overloads in process_image() and make_output_path().

Changes

• process_image(): Removed try/catch around std::filesystem::exists(),
  now uses std::filesystem::exists(path, ec) with explicit error_code
  handling
• make_output_path(): Updated exists() and create_directory() calls
  to use error_code overloads
• Preserves existing Status::FilesystemError and Status::InputFileNotFound
  behavior

Why

The C++ standard library allows querying filesystem operations with
error_code instead of exceptions. This avoids exception-based control
flow for expected filesystem failures and is consistent with modern
C++ best practices.

Closes #275

[linux-foundation-easycla]

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[antond-weta]

Thanks for looking into this. I see you included the changes from 278 here. It is better to only have relevant changes in each PR. The 278 was fine, apart from missing the CLA.

Unfortunately we can not accept contributions without a signed CLA. Please get that sorted if you can.