Keep dive computer BLE identities device-local

[mikecarr]

Summary

Addresses #645, where the same physical dive computer can appear as separate records on different Apple devices.

CoreBluetooth identifiers are host-specific, so the synced bluetoothAddress must not be used as the computer identity. This PR:

• Keeps BLE addresses local to each device and excludes them from sync export/import.
• Prevents incoming records or conflict resolution from overwriting a local BLE address.
• After a newly discovered computer downloads successfully, matches it by manufacturer, model, and serial number and rebinds the current device-local address to the existing record.
• Creates a new record when the stable hardware identity is genuinely new.

This handles the Petrel 3/ssss scenario without conflating computers of the same model with different serial numbers. Existing duplicate records are not automatically merged by this PR.

Validation

• flutter test test/features/import_wizard/data/adapters/dive_computer_adapter_test.dart
• flutter test test/core/services/sync/sync_serializer_fetch_record_test.dart
• dart analyze on all changed implementation and test files
• git diff --check

[github-actions]

📦 Build artifacts for this PR · commit 93ff44e

Platform	Download
Android (APK)	android-apk
macOS	macos-build
Windows	windows-build
Linux	linux-build

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[codecov]

Codecov Report

❌ Patch coverage is 68.00000% with 16 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ta/repositories/dive_computer_repository_impl.dart	0.00%	15 Missing ⚠️
lib/core/database/database.dart	0.00%	1 Missing ⚠️

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