feat(auth): add Authlib-backed OAuth adapter (related to #1240) #1062

Job	Run time
checks / readme-snippets	11s
checks / pre-commit	32s
checks / test (3.12, locked, ubuntu-latest)	54s
checks / test (3.12, lowest-direct, windows-latest)	3m 33s
checks / test (3.11, locked, ubuntu-latest)	50s
checks / test (3.10, locked, ubuntu-latest)	47s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 13s
checks / test (3.13, lowest-direct, ubuntu-latest)	48s
checks / test (3.11, lowest-direct, ubuntu-latest)	49s
checks / test (3.11, locked, windows-latest)	3m 13s
checks / test (3.10, lowest-direct, windows-latest)	2m 43s
checks / test (3.10, lowest-direct, ubuntu-latest)	50s
checks / test (3.12, locked, windows-latest)	3m 9s
checks / test (3.14, lowest-direct, windows-latest)	2m 36s
checks / test (3.10, locked, windows-latest)	2m 20s
checks / test (3.13, locked, ubuntu-latest)	44s
checks / test (3.13, locked, windows-latest)	2m 43s
checks / test (3.12, lowest-direct, ubuntu-latest)	57s
checks / test (3.13, lowest-direct, windows-latest)	2m 48s
checks / test (3.14, locked, windows-latest)	3m 21s
checks / test (3.14, locked, ubuntu-latest)	2m 19s
checks / test (3.11, lowest-direct, windows-latest)	2m 46s
all-green	3s
	40m 9s

Provide feedback