feat(app): add UnifiedPush support for github flavor

[wax911]

AniTrend Pull Request

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Description

Implements #202 by adding UnifiedPush support to the github flavor as a non-Google push transport.

This change adds the UnifiedPush connector dependency and GitHub-flavor manifest services, wires startup registration through a flavor-specific initializer and Koin module, and persists the active UnifiedPush endpoint through the repo's data/settings + Settings pattern instead of a standalone preference wrapper. It also keeps the Google flavor on Firebase Messaging unchanged.

Verification:

• ./gradlew --quiet :app:testGithubDebugUnitTest --tests co.anitrend.push.PushRegistrationCoordinatorTest
• ./gradlew --quiet :app:compileGithubDebugKotlin
• ./gradlew --quiet :app:compileGoogleDebugKotlin
• ./gradlew --quiet spotlessApply

Screenshots:

N/A

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Enhancement (Improves existing functionality)

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owners to license your work under the terms of the GPL v3 License.

[codacy-production]

Not up to standards ⛔

🔴 Issues 2 medium

Alerts:
⚠ 2 issues (≤ 0 issues of at least minor severity)

Results:
2 new issues

Category	Results
Complexity	2 medium

View in Codacy

🟢 Metrics 29 complexity

Metric	Results
Complexity	29

View in Codacy

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[github-actions]

Auto approved automated PR