[FIX] Delete empty output files instead of leaving 0-byte files (#1282)

[cfsmp3]

Summary

• When using --output-field both, CCExtractor creates separate output files for each field
• If one field has no captions (e.g., CC3 when only CC1 has data), a 0-byte file was left behind
• This fix checks file size in dinit_write() before closing - if empty, deletes the file

Approach

This is a simpler approach than PR #1793 (deferred file creation):

• Files are still created at initialization (no changes to init path)
• At cleanup, if a file is empty (0 bytes), it's deleted with an informational message
• Minimal code change (1 file, ~12 lines)

Test Results

$ ccextractor sample.ts --output-field both -o /tmp/test.srt
...
Deleted empty output file: /tmp/test_2.srt

Only the file with actual captions remains.

Fixes #1282

🤖 Generated with Claude Code

[ccextractor-bot]

CCExtractor CI platform finished running the test files on windows. Below is a summary of the test results, when compared to test for commit e3b0def...:

Report Name	Tests Passed
Broken	13/13
CEA-708	14/14
DVB	6/7
DVD	3/3
DVR-MS	2/2
General	24/27
Hardsubx	1/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	80/86
Teletext	21/21
WTV	13/13
XDS	34/34

Your PR breaks these cases:

• ccextractor --autoprogram --out=srt --latin1 --quant 0 85271be4d2...
• ccextractor --autoprogram --out=ttxt --latin1 1974a299f0...
• ccextractor --autoprogram --out=ttxt --latin1 --ucla dab1c1bd65...
• ccextractor --out=srt --latin1 --autoprogram 29e5ffd34b...
• ccextractor --out=spupng c83f765c66...
• ccextractor --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...
• ccextractor --startcreditsnotbefore 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...
• ccextractor --startcreditsnotafter 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...
• ccextractor --startcreditsforatleast 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...
• ccextractor --startcreditsforatmost 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9...

It seems that not all tests were passed completely. This is an indication that the output of some files is not as expected (but might be according to you).

Check the result page for more info.