Feat: Add "Check for updates" functionality to the SDK

[kirre-bylund]

Summary

Adds an automatic SDK update checker to the Unity Editor, notifying developers when a newer version is available on GitHub Releases. Targets users who installed via .unitypackage, .tgz, or Git URL — UPM Registry installs are skipped since the Package Manager already handles update badges.

Closes #1603.

Changes

Runtime/Game/Resources/LootLockerConfig.cs (bugfix)

• Fixes stale sdk_version after SDK upgrades on disk. Previously StoreSDKVersion() early-outed when sdk_version was already populated, so the version was never refreshed after updating the SDK files. Now it fires OnSdkVersionDetermined immediately with the cached value for responsiveness, then always re-queues Client.List() to get the fresh authoritative version.
• Adds public static bool SdkVersionDetermined so [InitializeOnLoad] subscribers that register after the event has already fired can still act on it without subscribing.
• Adds public static event Action OnSdkVersionDetermined — raised once each time the SDK version is resolved.

Runtime/Editor/UpdateChecker/LootLockerUpdateChecker.cs (feature)

• [InitializeOnLoad] static class LootLockerUpdateChecker with:
  • Startup delay (StartupDelaySeconds = 180.0, configurable in source) so the notification doesn't pop during heavy project loads.
  • After the delay: checks SdkVersionDetermined and either runs immediately or subscribes to OnSdkVersionDetermined.
  • 24 h throttle — at most one automatic check per day, stamped in EditorPrefs.
  • UPM Registry detection via PackageInfo.FindForAssembly — skips automatic check, shows an informational dialog on manual check.
  • Silence options persisted in EditorPrefs (global per machine):
    • Skip This Version
    • Remind in 7 Days
    • Never Notify
• [MenuItem("Window/LootLocker/Check for Updates")] — manual trigger that bypasses throttle and silence settings.
• LootLockerUpdateNotificationWindow — small non-blocking EditorWindow showing installed vs. latest version with four action buttons.
• Version comparison is numeric major.minor.patch (not lexicographic).

Looks

Testing

• Confirmed automatic check fires after startup delay with correct sdk_version resolved.
• Confirmed 24 h throttle suppresses duplicate checks within the same day.
• Confirmed manual check works regardless of throttle/silence state.
• UPM Registry install correctly skips auto-check.

[Copilot]

Pull request overview

Adds an Editor-only SDK update checker that queries GitHub Releases and notifies developers when a newer LootLocker Unity SDK version is available, while also improving how the SDK version is resolved/stored in the editor.

Changes:

• Adjusts editor-time SDK version resolution in LootLockerConfig and exposes an event/flag for “version resolved”.
• Adds an Editor update checker with automatic (throttled) startup checks plus a manual menu item, including a small notification window.
• Adds Unity .meta assets for the new Editor folder and script.

Reviewed changes

Copilot reviewed 2 out of 4 changed files in this pull request and generated 6 comments.

File	Description
Runtime/Game/Resources/LootLockerConfig.cs	Adds SDK-version-determined event/flag and changes when/how the version lookup is queued.
Runtime/Editor/UpdateChecker/LootLockerUpdateChecker.cs	Implements GitHub Releases update check, throttling/silencing options, menu item, and notification window.
Runtime/Editor/UpdateChecker/LootLockerUpdateChecker.cs.meta	Adds metadata for the new editor script.
Runtime/Editor/UpdateChecker.meta	Adds metadata for the new editor folder.

Files not reviewed (2)

• Runtime/Editor/UpdateChecker.meta: Language not supported
• Runtime/Editor/UpdateChecker/LootLockerUpdateChecker.cs.meta: Language not supported