Save last server location

[jigar-f]

This pull request introduces several improvements to the VPN server selection and event handling logic, ensuring that user-selected servers are correctly persisted and restored, and that automatic server updates do not override user choices. It also adds new methods for more granular state management and improves logging and code clarity.

VPN server selection and persistence improvements:

• Updated StartVPN in vpn_tunnel.go to restore the user's previously selected server on tunnel startup, falling back to auto-selection only if no prior selection exists. This ensures user choices persist across VPN restarts, especially on Android.
• In server_selection.dart, ensured that switching to auto server selection explicitly updates the state before navigating, preventing stale or inconsistent UI.

Event handling enhancements:

• Modified AppEventNotifier to process server-location events only when the user is in auto mode, preventing unwanted overrides of custom server selections.
• Improved logging and code formatting in app_event_notifier.dart for better readability and maintainability. [1] [2]

State management additions:

• Added updateAutoLocationMetadata and switchToAuto methods to ServerLocationNotifier, allowing for metadata updates and seamless switching to auto mode without losing previous custom server information.

Other:

• Minor formatting fix in go.mod for the replace directive.

[jigar-f]

Depends on getlantern/radiance#412

[Copilot]

Pull request overview

This PR aims to persist and restore the user’s last-selected VPN server across restarts, while preventing auto-location updates/events from overriding explicit user selections.

Changes:

• Restore persisted server selection on tunnel startup (fallback to auto-connect if none/invalid).
• Add notifier methods for switching to auto mode and updating auto-location metadata.
• Gate handling of server-location push events to avoid overwriting custom selections; small UI state update when switching to Smart Location.
• Update Radiance dependency version.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
lib/features/vpn/server_selection.dart	Ensures switching to Smart Location updates provider state before navigating away.
lib/features/vpn/provider/server_location_notifier.dart	Adds helper APIs for auto-mode switching and auto-location metadata updates with persistence.
lib/features/home/provider/app_event_notifier.dart	Prevents server-location events from overriding non-auto user selections; logging formatting cleanup.
lib/features/home/home.dart	Refactors settings tile layout; routing mode tile visibility behavior changes.
lantern-core/vpn_tunnel/vpn_tunnel.go	Restores persisted server selection on VPN start, falling back to auto-connect.
go.mod	Bumps github.com/getlantern/radiance version.
go.sum	Updates checksums for bumped dependency version.

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