Stabilize media upload paths

[subzeroid]

Summary

Media upload remains one of the most visible user-facing areas where regressions cause immediate frustration.

This issue tracks hardening upload-related paths and protecting them with better tests.

Problem areas

Repeated reports mention:

• clip_upload() failures
• reels upload regressions
• story/photo upload breakage after dependency or payload changes
• differences between session-based and fresh-login upload behavior

Proposed scope

• review recent upload-related regressions in photo/video/reel/story paths
• add focused regression tests around recent breakages
• verify payload assumptions against current extractor/type expectations
• improve resilience to missing or changed response fields

Definition of done

• the main upload paths are covered by stronger regression tests
• recent upload regressions are protected from reappearing
• common upload failures produce clearer behavior and diagnostics

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Landed another concrete hardening pass for media upload paths in b081936:
b081936

What changed:

• added a shared helper for upload configure responses so photo_upload, video_upload, album_upload, clip_upload, and igtv_upload no longer crash with a raw extractor error when Instagram returns a truthy configure response without a media payload
• these paths now raise a clearer domain-level configure error instead
• preserved compatibility for flows where the media still only appears in last_json
• added new mock-only UploadRegressionTestCase coverage and wired it into the automatic test-compat CI smoke set

This gives #2421 a first real regression-protected hardening slice without needing fresh HAR/live-account repros yet.

[subzeroid]

Another upload hardening slice landed in 4f37a4f:
4f37a4f

What changed:

• photo_upload_to_story() and video_upload_to_story() now raise a clear *ConfigureStoryError when Instagram returns a truthy configure response without a media payload instead of crashing in the extractor
• video_upload_to_direct() now raises a clear error when configure succeeds without message_metadata
• added more mock-only regression coverage for these story/direct upload edge cases

So #2421 now covers both feed uploads and story/direct upload payload-shape regressions with automatic CI-backed tests.

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Another set of upload hardening fixes landed after the initial passes:

• 4f37a4f — story/direct upload payload handling
  4f37a4f
• 53fd86f — cutout sticker configure handling
  53fd86f
• da01a83 — reel music upload cleanup / temp file safety
  da01a83
• 8328822 — album upload format handling and clearer errors
  8328822

What is covered now:

• feed upload configure responses without media
• story upload configure responses without media
• direct story upload configure responses without message_metadata
• cutout sticker configure responses without media
• safer cleanup in clip_upload_as_reel_with_music()
• clearer album upload behavior for empty input, unsupported suffixes, and .png

All of these slices were backed by mock-only regression tests, so #2421 now has stronger automatic coverage across feed/story/direct/cutout/album upload edge cases.