feat(ipc): add SSE status event streaming to clients in real-time

[garmr-ulfr]

This pull request introduces a new server-sent events (SSE) endpoint for streaming VPN status updates and refactors the VPN status handling throughout the IPC server. The changes replace the previous string-based status checks with a strongly-typed VPNStatus enum, update endpoint handlers to use the new status values, and remove legacy status management logic. Additionally, HTTP/2 protocol handling is improved to support streaming responses. The most important changes are grouped below.

VPN Status Event Streaming

• Added a new SSE endpoint (statusEventsEndpoint) and handler (statusEventsHandler) for real-time VPN status updates, including a client implementation and test coverage. (vpn/ipc/events.go, vpn/ipc/events_client.go, vpn/ipc/events_test.go, vpn/ipc/endpoints.go) [1] [2] [3] [4]

Refactoring Status Management

• Replaced legacy string-based status checks (e.g., StatusRunning, StatusClosed) with the new VPNStatus enum values (Connected, Disconnected, etc.) across all endpoint handlers and service logic. (vpn/ipc/server.go, vpn/ipc/connections.go, vpn/ipc/clash_mode.go, vpn/ipc/group.go, vpn/ipc/outbound.go, telemetry/connections.go, vpn/ipc/status.go) [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]

• Removed legacy status constants and the setVPNStatus method, simplifying the codebase and centralizing status updates via the new event stream. (vpn/ipc/server.go, vpn/ipc/status.go) [1] [2] [3]

HTTP/2 Streaming Support

• Introduced explicit HTTP/2 protocol handling and removed response buffering for SSE endpoints to enable efficient streaming and long-lived connections. (vpn/ipc/http.go, vpn/ipc/server.go) [1] [2] [3]

Endpoint Routing Improvements

• Grouped standard routes under a tracer middleware and separated SSE routes to avoid response buffering, ensuring proper handling of streaming connections. (vpn/ipc/server.go)

These changes modernize the IPC server's status handling, introduce real-time event streaming, and improve protocol support for streaming connections.

[Copilot]

Pull request overview

This pull request modernizes the VPN status handling by introducing a strongly-typed VPNStatus enum to replace string-based status values, adds a new SSE endpoint for real-time status event streaming, and improves HTTP/2 support for long-lived streaming connections. The changes centralize status management through an event-driven architecture where status updates are emitted as StatusUpdateEvent events rather than being managed directly by the IPC server.

Changes:

• Introduced VPNStatus enum type with values: Connecting, Connected, Disconnecting, Disconnected, Restarting, and ErrorStatus
• Added SSE endpoint /status/events for streaming VPN status updates to clients in real-time
• Refactored status management to use event-driven architecture with StatusUpdateEvent emissions from the tunnel layer
• Updated HTTP server configuration to support HTTP/2 and removed WriteTimeout to enable long-lived SSE connections

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
vpn/ipc/events.go	Implements SSE handler for streaming status events with StatusUpdateEvent type definition
vpn/ipc/events_client.go	Client implementation for consuming status event stream with retry logic
vpn/ipc/events_test.go	Test coverage for status event streaming handler
vpn/ipc/endpoints.go	Adds /status/events endpoint constant
vpn/ipc/server.go	Introduces VPNStatus enum, removes legacy status management, configures HTTP/2, and separates SSE routes from tracer middleware
vpn/ipc/status.go	Updates GetStatus and statusHandler to use VPNStatus type, removes legacy string constants
vpn/ipc/http.go	Configures HTTP/2 protocol support for client and server transports
vpn/ipc/connections.go	Updates status comparisons from StatusRunning to Connected
vpn/ipc/clash_mode.go	Updates status comparisons from StatusRunning to Connected
vpn/ipc/group.go	Updates status comparisons from StatusRunning to Connected
vpn/ipc/outbound.go	Updates status comparisons from StatusRunning to Connected
vpn/tunnel.go	Implements status management with atomic.Value, emits StatusUpdateEvent on status changes, adds Restarting status handling
vpn/service.go	Updates Status() return type to VPNStatus, sets Restarting status during restart
vpn/vpn.go	Updates isOpen check from StatusRunning to Connected
vpn/vpn_test.go	Updates mock service to use VPNStatus type and Connected constant
vpn/tunnel_test.go	Updates test assertions from StatusRunning/StatusClosed to Connected/Disconnected
telemetry/connections.go	Updates status comparison from StatusRunning to Connected

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