feat(tray): enforce single instance and expose reachable URLs

[rsdmike]

A second invocation now detects the running instance via a per-user
flock (Unix) or named mutex (Windows), opens the existing tray's URL
in the browser, and exits cleanly rather than racing on port 8181.
The lock FD is inherited across the background re-exec so it survives
parent exit.

Default HTTP_HOST changes from "localhost" to wildcard so the tray
is reachable from other devices on the LAN. The tray menu and
startup log enumerate every routable IPv4, filtering virtual bridges
(docker, veth, br-, tun/tap, virbr, vmnet, vboxnet, wg, zt, awdl,
llw) and deduping.

When bound to a wildcard, the UI's injected ##CONSOLE_SERVER_API##
resolves to a relative URL so same-origin fetches match the user's
actual host/SNI.

Refs: Package Console as an installer #870

[codecov]

Codecov Report

❌ Patch coverage is 93.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 41.47%. Comparing base (3c696e6) to head (9780cea).

Files with missing lines	Patch %	Lines
internal/controller/httpapi/ui.go	92.85%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #986      +/-   ##
==========================================
+ Coverage   41.41%   41.47%   +0.06%     
==========================================
  Files         134      134              
  Lines       12321    12334      +13     
==========================================
+ Hits         5103     5116      +13     
  Misses       6672     6672              
  Partials      546      546              

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[Copilot]

Pull request overview

This PR updates tray-mode startup behavior to enforce a single running instance, expose LAN-reachable URLs when binding wildcard hosts, and make the UI use same-origin API calls for wildcard bindings.

Changes:

• Default HTTP binding changes from localhost to wildcard/empty host.
• Tray mode now computes reachable URLs, logs them, and attempts single-instance handling on Unix/Windows.
• UI config injection now returns a relative API base for wildcard hosts and adds tests for URL generation.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
internal/controller/httpapi/ui.go	Adds wildcard host detection and API base URL construction via net.JoinHostPort.
internal/controller/httpapi/ui_test.go	Adds tests for API base URL generation.
config/config.go	Makes HTTP_HOST optional and defaults it to wildcard binding.
config/config_test.go	Updates default host expectation.
cmd/app/tray.go	Adds reachable URL discovery, tray startup logging, and single-instance invocation flow.
cmd/app/tray_windows.go	Adds named-mutex based single-instance handling and browser/message surfacing.
cmd/app/tray_unix.go	Adds flock-based single-instance handling and lock FD inheritance across re-exec.
cmd/app/tray_test.go	Adds tray helper tests for wildcard hosts and virtual interface filtering.
.env.example	Documents empty HTTP_HOST as binding all interfaces.

Comments suppressed due to low confidence (2)

cmd/app/tray.go:49

• The PR description says the tray menu enumerates every reachable URL, but this still passes only primaryURL into tray.Config, whose menu renders a single status/open URL. The startup log lists all URLs, but the tray UI does not expose the additional LAN addresses.

	trayManager := tray.New(tray.Config{
		AppName:  "DMT Console",
		URL:      primaryURL,
		Headless: isHeadlessBuild,

cmd/app/tray_windows.go:36

• If creating the named mutex fails, the function returns and startup proceeds without single-instance protection, so duplicate tray processes can still race on the HTTP port. Treat mutex creation failures as startup errors or provide a fallback rather than silently disabling the guard.

	handle, _, lastErr := createMutex.Call(0, 0, uintptr(unsafe.Pointer(namePtr)))
	if handle == 0 {
		return

[RosieAMT]

🎉 This PR is included in version 1.27.0 🎉

The release is available on:

• GitHub release
• v1.27.0

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