Refactor accessibility command queue and utilities; add keyboard/media helpers and multimodal serialization

[Android-PowerUser]

Motivation

• Improve reliability and concurrency of accessibility command processing by replacing ad-hoc queues and flags with a dedicated AccessibilityCommandQueue abstraction.
• Factor platform-specific helpers (media projection starter, accessibility state checker, keyboard visibility observer) out of MainActivity to simplify lifecycle management and reduce duplicated code.
• Centralize command model and parsing, and add utilities for app name mapping, string similarity, image handling and serialization to support robust multimodal/photo reasoning features.

Description

• Added AccessibilityCommandQueue, AccessibilityServiceStateChecker, KeyboardVisibilityObserver, and MediaProjectionServiceStarter to encapsulate queueing, state checks, keyboard detection, and service start logic respectively, and wired them into MainActivity and ScreenOperatorAccessibilityService.
• Reworked ScreenOperatorAccessibilityService to use AccessibilityCommandQueue and AccessibilityServiceStateChecker and updated queue processing logic to use the new API (enqueue, tryAcquireProcessing, releaseProcessing, etc.).
• Introduced a shared Command sealed class in util/Command.kt and substantially refactored CommandParser to be more robust (pattern metadata, overlap handling, single-instance command deduplication and logs).
• Added multimodal helpers: PhotoReasoningSerialization for streaming JSON and bitmap->Base64 conversion, and MainActivityBridge to safely access MainActivity context/API key from view models; updated PhotoReasoningViewModel to use these utilities and to delegate AI calls to the foreground service.
• Reworked app mapping logic (AppMappings + AppNamePackageMapper) to use structured definitions and string-similarity matching via a new StringSimilarity util, improved normalization and caching behavior.
• Various utility and preferences improvements: ImageUtils cleanup, CoordinateParser simplification, GenerationSettingsPreferences, ChatHistoryPreferences, SystemMessagePreferences, SystemMessageEntryPreferences, and UserInputPreferences refactored for safer SharedPreferences access, default population, and clearer keys/serializers.

Testing

• Built the Android app with ./gradlew assembleDebug to verify compilation with the refactor; build succeeded.
• Ran unit tests with ./gradlew test (project unit tests) and static checks; they completed successfully.

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Codex Task

[amazon-q-developer]

This PR implements significant refactoring to improve accessibility command processing, lifecycle management, and code organization. However, critical thread-safety bugs have been identified in the new AccessibilityCommandQueue class that must be fixed before merge.

Critical Issues (Must Fix):

• 🛑 Thread-safety bugs in AccessibilityCommandQueue: The clearAndUnlock, enqueue, peek, poll, size, and isEmpty methods lack synchronization, which can cause race conditions, lost commands, and ConcurrentModificationExceptions when accessed by multiple threads simultaneously.

Summary:
The refactoring successfully:

• Introduces dedicated abstractions for command queue, service state checking, keyboard visibility, and media projection starting
• Extracts Command sealed class and improves CommandParser with better pattern handling and deduplication
• Adds multimodal helpers for streaming JSON, bitmap serialization, and MainActivity bridge
• Refactors app mapping with structured definitions and string similarity matching
• Improves SharedPreferences handling across utility classes

Once the thread-safety issues are resolved with proper synchronization, this refactoring will significantly improve code maintainability and reliability.

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