test: Phase 4 - Feature module tests (154 new tests)

[ksalhab89]

Summary

Phase 4: Feature module tests. Adds 154 new unit tests across 6 modules.

Builds on Phase 3 (#3539).

New Tests

Module	Tests	Classes
common:search	55	SearchTextUtil, ArabicCharacterHelper, DefaultSearcher, ArabicSearcher
feature:linebyline	44	LineCalculation, AyahSelectionExtension, SelectionHelper, QuranLineByLineSettingsPresenter
feature:audiobar	12	AudioBarEventRepository
common:audio	19	PartiallyDownloadedSuraExtension, AudioStatusRepository
feature:audio	17	AudioFileCheckerImpl
feature:qarilist	7	QariListPresenter

Production Changes

One minimal interface extraction:

• QariDownloadInfoSource interface added to common:audio
• QariDownloadInfoManager implements it
• QariListPresenter constructor param changed to interface
• DI binding added in ApplicationModule

New Fakes

• FakeSettings — implements com.quran.data.dao.Settings
• FakeQariDownloadInfoSource — MutableStateFlow-backed
• FakeHashCalculator — deterministic hash for AudioFileCheckerImpl tests

Test Plan

• All 6 module test suites pass (2 consecutive runs, 0 flaky)
• ./gradlew :app:testMadaniDebugUnitTest — regression check pass

[github-actions]

OLD: app-madani-debug.apk (signature: V1, V2)
NEW: app-madani-debug.apk (signature: V1, V2)

          │            compressed            │           uncompressed           
          ├───────────┬───────────┬──────────┼───────────┬───────────┬──────────
 APK      │ old       │ new       │ diff     │ old       │ new       │ diff     
──────────┼───────────┼───────────┼──────────┼───────────┼───────────┼──────────
      dex │  20.3 MiB │  20.3 MiB │   +810 B │  51.3 MiB │  51.3 MiB │ +3.1 KiB 
     arsc │   2.1 MiB │   2.1 MiB │      0 B │   2.1 MiB │   2.1 MiB │      0 B 
 manifest │   5.7 KiB │   5.7 KiB │      0 B │  26.6 KiB │  26.6 KiB │      0 B 
      res │   1.8 MiB │   1.8 MiB │      0 B │     2 MiB │     2 MiB │      0 B 
   native │ 112.3 KiB │ 110.7 KiB │ -1.6 KiB │  36.5 KiB │  36.5 KiB │      0 B 
    asset │   1.8 MiB │   1.8 MiB │      0 B │   4.1 MiB │   4.1 MiB │      0 B 
    other │ 200.1 KiB │ 200.1 KiB │    -15 B │ 501.8 KiB │ 501.8 KiB │      0 B 
──────────┼───────────┼───────────┼──────────┼───────────┼───────────┼──────────
    total │  26.3 MiB │  26.3 MiB │   -825 B │    60 MiB │  60.1 MiB │ +3.1 KiB