Firebase Apple 12.15.0 renames Gemini model, adds App Check, Firestore fix

The Firebase Apple SDK (12.15.0) is now available. For more details, see the Firebase Apple SDK release notes.

To install this SDK, see Add Firebase to your project.

What's Changed

• [Core] Require swift-tools-version:6.1 in Package.swift by @andrewheard in https://github.com/firebase/firebase-ios-sdk/pull/16223
• [AI] Rename GeminiModel to GeminiLanguageModel by @andrewheard in https://github.com/firebase/firebase-ios-sdk/pull/16227
• fix(appcheck): remove redundant fac debug token logging by @ncooke3 in https://github.com/firebase/firebase-ios-sdk/pull/16197
• feat(appcheck): Add new internal, default provider by @ncooke3 in https://github.com/firebase/firebase-ios-sdk/pull/16190
• docs(appcheck): prefer 'AppCheckDebugToken' for debug env var injection by @ncooke3 in https://github.com/firebase/firebase-ios-sdk/pull/16230
• feat(appcheck): add helpful log for registering debug tokens by @ncooke3 in https://github.com/firebase/firebase-ios-sdk/pull/16232
• [AI] Add Hashable conformance to model config types by @andrewheard in https://github.com/firebase/firebase-ios-sdk/pull/16233
• [AI] Add public init for GeminiLanguageModel by @andrewheard in https://github.com/firebase/firebase-ios-sdk/pull/16234
• feat(ai): add app check dependency by @ncooke3 in https://github.com/firebase/firebase-ios-sdk/pull/16185
• Readme improvements by @paulb777 in https://github.com/firebase/firebase-ios-sdk/pull/16238
• [AI] Revert rename of GeminiModel to GeminiLanguageModel by @andrewheard in https://github.com/firebase/firebase-ios-sdk/pull/16237
• Migrate repo dev content from README to CONTRIBUTING by @paulb777 in https://github.com/firebase/firebase-ios-sdk/pull/16239
• [AI] Add readme banner for FMF adapter by @paulb777 in https://github.com/firebase/firebase-ios-sdk/pull/16248
• Analytics 12.15.0 by @htcgh in https://github.com/firebase/firebase-ios-sdk/pull/16250
• fix(firestore): remove designated initializers for force_index by @dlarocque in https://github.com/firebase/firebase-ios-sdk/pull/16229
• fix(ai): Handle Xcode 27 LanguageModelSession.Error collision by @andrewheard in https://github.com/firebase/firebase-ios-sdk/pull/16257
• feat(appcheck): implement RecaptchaEnterpriseProvider and tests by @ncooke3 in https://github.com/firebase/firebase-ios-sdk/pull/16155
• [AI] Support SpeechConfig in Text-To-Speech by @milaGGL in https://github.com/firebase/firebase-ios-sdk/pull/16226
• try building docc docs on swift package index by @morganchen12 in https://github.com/firebase/firebase-ios-sdk/pull/16262

Full Changelog: https://github.com/firebase/firebase-ios-sdk/compare/12.14.0...12.15.0