All factory included socialite packages are using relatively short keys like GOOGLE_CLIENT_ID, I think it would make reading the config and env easier if this package would use APPLE_CLIENT_ID. The unnecessary (in my opinion) SIGN_IN_WITH_ part just adds visual clutters.

Acceptance Criteria

• Config keys are shortened to be concise (e.g. apple.client_id instead of longer equivalents)
• Old config key names are aliased with a deprecation warning for one major version
• README and published config file reflect the new keys

Test Coverage

• Integration test: package works with new short config keys
• Deprecation test: old config keys trigger a deprecation warning, not a fatal error

WSJF Priority Score

• Score: 2.00
• User/Business Value: 3 (Minor DX improvement; existing keys work fine)
• Time Criticality: 1 (No urgency; no breaking impact if deferred)
• Risk Reduction/Opportunity Enablement: 2 (Cleaner API reduces config typos)
• Job Size: 3 points (S — rename + deprecation aliases + README)
• Calculation: (3 + 1 + 2) ÷ 3 = 2.00