Export Screen Updates

[ErikJour]

Description

When setting time values in the export screen, there was a previous bug in which leaving the menu and then returning to it cleared the export timing values. Furthermore, export timing was truncated, losing timing precision.

Changes

• Fixed export screen state persistence so values are retained when navigating away and back
• Improved timecode timing precision on export — start/end times are now stored in milliseconds and converted to seconds in the processor for accurate sample-level timing.
• Updatedvalidate_file_checksum, pp_validate_file_checksum, LoggerTest, and verify_metadata

Validation and Acceptance Criteria

Briefly describe how this PR meets any acceptance criteria defined in the linked issue.
-All tests are passing

[joelmacx]

I like these changes, just a bit of cleanup to do 👍

Did we validate in at least Pro Tools and Reaper DAWs as well?

[joelmacx]

I'm curious why we're using milliseconds instead of sample rate and sample count directly? From the UI the user should configure the time in seconds/milliseconds but on the backend this should likely be sample count to be as accurate as possible, no? Curious to hear some more thoughts here

[ErikJour]

That will give even better precision. The issue was that seconds were stored as ints, and we were losing frames on export. Milliseconds fixed this, but moving to samples will be cleaner.