fix(auto-upload): restart folder runs that stay enqueued on rescan

[ToteMeiSter]

Refs #17439

Problem

Every synced folder has its own one-time AutoUploadWorker run (immediate_files_sync_<id>), enqueued with ExistingWorkPolicy.KEEP. isAutoUploadScheduled treats every unfinished run as active. When a run stays in ENQUEUED, every later request for that folder is dropped: the content observer, app start and AutoUploadRescanWorker. AutoUploadRescanWorker calls cancelEnqueuedAutoUploads() to get a clean start, but that function only cancels runs with periodicityInfo != null. Per-folder runs are one-time work, so nothing is cancelled and the folder stays stuck.

Change

cancelEnqueuedAutoUploads() cancels every enqueued AutoUploadWorker run. Runs tagged _ignore_power_saving ("sync now") stay, because restarting them would drop the override. The rescan then enqueues the folders again through startAutoUploadForEnabledSyncedFoldersIfNotActive.

Notes

• Running and finished runs are not touched.
• Leftover periodic AutoUploadWorker runs from older versions are still cancelled, as before.
• If the constraint of a run cannot be met on the device, enqueueing it again does not guarantee a start. The change makes the rescan recover runs that are stuck for other reasons.
• Touches only BackgroundJobManagerImpl and its test. No file overlap with the other three PRs (fix(auto-upload): start auto upload right after resuming global upload pause #17806, fix(sharing): download file before "Send copy to" #17807, fix(share): send original file instead of cached thumbnail #17808); trial merge of all four is clean.

How to test

• Unit: BackgroundJobManagerImplTest (3 tests: an enqueued folder run is cancelled; running and finished runs are kept; an enqueued "sync now" run is kept). The first test fails without the change (WantedButNotInvoked).
• Device: Checked on a HUAWEI Mate X7 (DEL-LX9, EMUI 15.0.0, Android 12) with a test build: works, auto upload from several folders runs.

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not needed
• 🔙 Backport requests are created or not needed: /backport to stable-xx.x
• 📅 Milestone is set
• 🌸 PR title is meaningful (if it should be in the changelog: is it meaningful to users?)

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI

The change was drafted with Claude Code (Assisted-by: Claude-Code:claude-opus-5-5).

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
.../nextcloud/client/jobs/BackgroundJobManagerImpl.kt	0.00%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!