fix: add sdk version to cache keys for configs

[kaushalkapasi]

• fix: updates cache keys to include the SDK Version
• fix: cleanup cached configs from other SDK Versions
• chore: update tests for Cached Configs and Config Migrations

[Copilot]

Pull Request Overview

This PR ensures that all configuration cache keys include the SDK version and adds cleanup for any old, non-versioned entries.

• Prefixes config keys with VERSION_<sdkVersion> in both the service and tests
• Implements cleanupDeprecatedCachedConfigs() to remove stale entries from previous SDK versions
• Updates unit tests to expect and verify versioned cache keys

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
DevCycleTests/Models/DevCycleUserTest.swift	Tests updated to seed and assert on versioned cache keys
DevCycle/Models/Cache.swift	Added versionPrefix, adjusted CacheKeys, and added cleanup for deprecated keys

Comments suppressed due to low confidence (3)

DevCycle/Models/Cache.swift:139

• The migration logic currently uses the versioned key CacheKeys.identifiedConfigKey as the oldKey, so legacy data stored under the unversioned key won’t be migrated. Consider using the legacy constant (CacheKeys.identifiedConfig) for oldKey to correctly migrate pre-versioned data.

                return nil

DevCycle/Models/Cache.swift:135

• There is no unit test for cleanupDeprecatedCachedConfigs(). Adding a test to verify that non-versioned keys are removed when migrateLegacyCache() runs would improve coverage and prevent regressions.

    private func cleanupDeprecatedCachedConfigs() {

DevCycleTests/Models/DevCycleUserTest.swift:243

• [nitpick] The test’s versionPrefix omits the trailing dot present in CacheKeys.versionPrefix. Consider including the dot in this constant (e.g., "VERSION_\(PlatformDetails().sdkVersion).") to avoid manual concatenation and ensure consistency.

        let versionPrefix = "VERSION_\(PlatformDetails().sdkVersion)"

[kaushalkapasi]

Going to use the approach as defined in #244