Open the sync pull request straight from ankidroid:main

[float3]

• the fork keeps no main branch any more (deleted; the "Keep main" ruleset is removed)
• the job checks out ankiquest, fetches ankidroid/Anki-Android main, and if ankiquest is behind opens a PR with head ankidroid:main (skips if one is open)
• REST API instead of gh pr create: its --head owner:branch does not support organizations
• nothing is pushed any more, so UPSTREAM_SYNC_TOKEN only needs pull request access; still a PAT so the PR's CI runs
• conflicts: merge upstream into a branch from ankiquest and merge that; the upstream PR then shows as merged

[github-actions]

Snapshot diff report vs ankiquest. Open screenshot-diff for diffs.

• AnkiquestHomeScreenshotTest: 1 change
• DeckPickerScreenshotTest: 3 changes
• NavigationDrawerScreenshotTest: 1 change
• ReviewRemindersScreenshotTest: 5 changes

All 10 changed screenshots

AnkiquestHomeScreenshotTest

• today_320dp_compare.png

DeckPickerScreenshotTest

• deck_list_after_dismissing_create_deck_dialog_compare.png
• hierarchy_lines_collapsed_compare.png
• keyboard_open_scrolled_to_bottom_compare.png

NavigationDrawerScreenshotTest

• navigationDrawer_compare.png

ReviewRemindersScreenshotTest

• studyOptionsFragmentHost_scheduleReminders_compare.png
• studyOptionsFragmentHost_systemBars_compare.png
• studyOptionsFragmentHost_systemBars_scrolledToEnd_compare.png
• studyOptionsFragmentHost_troubleshooting_compare.png
• studyOptionsFragmentHost_troubleshooting_systemBars_compare.png